2012 New York Consolidated Laws
RPT - Real Property Tax
Article 18 - (1801 - 1806) PRESERVATION OF CLASS SHARE OF TAXES IN MUNICIPAL CORPORATIONS EXCEPT COUNTIES WITHIN A CITY, INCLUDED WITHIN THE BOUNDARIES OF A SPECIAL A
1803-A - Adjusted base proportions; determination.

 
    §  1803-a.  Adjusted  base proportions; determination. 1. Current base
  proportions. (a) For  each  tax  levy  based  upon  an  assessment  roll
  completed in nineteen hundred ninety-one and thereafter, the legislative
  body  of  each  special  assessing  unit  shall compute the current base
  proportion and certify to the commissioner the current base  proportion,
  the  current  percentage, and base percentage of each class and for each
  class for each portion included in its boundaries and  such  alterations
  made  to  such  current  base proportions made pursuant to paragraph (c)
  hereof no later than thirty days subsequent to the  date  on  which  the
  commissioner  certifies  class  equalization  rates  pursuant to section
  twelve hundred twelve of this chapter, pursuant  to  the  provisions  of
  this section.
    (b)  The  current  base proportion shall be determined pursuant to the
  following formula:
    (1) Divide the current percentage of each class by the base percentage
  of such class.
    (2) For each such class multiply the result from subparagraph  one  of
  this paragraph by the local base proportion of such class.
    (3)  Sum  the  products obtained in subparagraph two of this paragraph
  and divide the product for each class by such sum.
    (c)  Notwithstanding  the  provisions  of  paragraph   (b)   of   this
  subdivision,  the  current base proportion of any class shall not exceed
  the adjusted  base  proportion  or  adjusted  proportion,  whichever  is
  appropriate,  of  the  immediately  preceding  year  by  more  than five
  percent. Where the computation performed pursuant to  paragraph  (b)  of
  this  subdivision  would otherwise produce such result, the current base
  proportion of such class or  classes  shall  be  limited  to  such  five
  percent increase and the legislative body of such special assessing unit
  shall  alter the current base proportions of any or all of the remaining
  classes so that the sum of the current base proportions equals one.
    (d)  Notwithstanding  the  provisions  of  paragraph   (c)   of   this
  subdivision to the contrary, in a special assessing unit which is a city
  and  for  current  base  proportions  to  be  determined in such special
  assessing unit's fiscal year nineteen hundred ninety-five,  the  current
  base  proportion  of  any  class  shall  not  exceed  the  adjusted base
  proportion or adjusted proportion,  whichever  is  appropriate,  of  the
  immediately  preceding year by more than two and three-quarters percent.
  Where the computation  performed  pursuant  to  paragraph  (b)  of  this
  subdivision  would  otherwise  produce  such  result,  the  current base
  proportion of such class or classes shall be limited  to  such  two  and
  three-quarters percent increase and the legislative body of such special
  assessing  unit  shall  alter the current base proportions of any or all
  remaining classes so that the sum of the current base proportions equals
  one.
    (e)  Notwithstanding  the  provisions  of  paragraph   (c)   of   this
  subdivision to the contrary, in a special assessing unit which is a city
  and  for  current  base  proportions  to  be  determined in such special
  assessing unit's fiscal year nineteen hundred  ninety-six,  the  current
  base  proportion  of  any  class  shall  not  exceed  the  adjusted base
  proportion or adjusted proportion,  whichever  is  appropriate,  of  the
  immediately  preceding year by more than two and three-quarters percent.
  Where the computation  performed  pursuant  to  paragraph  (b)  of  this
  subdivision  would  otherwise  produce  such  result,  the  current base
  proportion of such class or classes shall be limited  to  such  two  and
  three-quarters percent increase and the legislative body of such special
  assessing  unit  shall  alter the current base proportions of any or all
  remaining classes so that the sum of the current base proportions equals
  one.

    (f)  Notwithstanding  the  provisions  of  paragraph   (c)   of   this
  subdivision to the contrary, in a special assessing unit which is a city
  and  for  current  base  proportions  to  be  determined in such special
  assessing unit's fiscal year nineteen hundred ninety-seven, the  current
  base  proportion  of  any  class  shall  not  exceed  the  adjusted base
  proportion or adjusted proportion, which ever  is  appropriate,  of  the
  immediately  preceding year by more than two and one-half percent. Where
  the computation performed pursuant to paragraph (b) of this  subdivision
  would otherwise produce such result, the current base proportion of such
  class  or  classes  shall  be  limited  to such two and one-half percent
  increase and the legislative body of such special assessing  unit  shall
  alter  the  current  base  proportion of any or all remaining classes so
  that the sum of the current base proportions equals one.
    (g)  Notwithstanding  the  provisions  of  paragraph   (c)   of   this
  subdivision to the contrary, in a special assessing unit which is a city
  and  for  current  base  proportions  to  be  determined in such special
  assessing unit's fiscal year nineteen hundred ninety-eight, the  current
  base  proportion  of  any  class  shall  not  exceed  the  adjusted base
  proportion or adjusted proportion,  whichever  is  appropriate,  of  the
  immediately  preceding year by more than two and one-half percent. Where
  the computation performed pursuant to paragraph (b) of this  subdivision
  would otherwise produce such result, the current base proportion of such
  class  or  classes  shall  be  limited  to such two and one-half percent
  increase and the legislative body of such special assessing  unit  shall
  alter  the  current  base  proportion of any or all remaining classes so
  that the sum of the current base proportions equals one.
    (h)  Notwithstanding  the  provisions  of  paragraph   (c)   of   this
  subdivision to the contrary, in a special assessing unit which is a city
  and  for  current  base  proportions  to  be  determined in such special
  assessing unit's fiscal year nineteen hundred ninety-nine,  the  current
  base  proportion  of  any  class  shall  not  exceed  the  adjusted base
  proportion or adjusted proportion,  whichever  is  appropriate,  of  the
  immediately  preceding year by more than two and one-half percent. Where
  the computation performed pursuant to paragraph (b) of this  subdivision
  would otherwise produce such result, the current base proportion of such
  class  or  classes  shall  be  limited  to such two and one-half percent
  increase and the legislative body of  such  special  assessing  unit  by
  local  law  shall  alter  the  current  base  proportions  of any or all
  remaining classes so that the sum of the current base proportions equals
  one.
    (i)  Notwithstanding  the  provisions  of  paragraph   (c)   of   this
  subdivision  to the contrary, in a special assessing unit that is a city
  and for current base  proportions  to  be  determined  in  such  special
  assessing  unit's  fiscal year two thousand, the current base proportion
  of any class shall not exceed the adjusted base proportion  or  adjusted
  proportion,  whichever is appropriate, of the immediately preceding year
  by more than two and one-half percent. Where the  computation  performed
  pursuant  to  paragraph  (b) of this subdivision would otherwise produce
  such result, the current base proportion of such class or classes  shall
  be limited to such two and one-half percent increase and the legislative
  body  of  such  special  assessing  unit  shall  alter  the current base
  proportion of any or all remaining  classes  so  that  the  sum  of  the
  current base proportions equals one.
    (j)   Notwithstanding   the   provisions  of  paragraph  (c)  of  this
  subdivision to the contrary, in a special assessing unit that is a  city
  and  for  current  base  proportions  to  be  determined in such special
  assessing  unit's  fiscal  year  two  thousand  one,  the  current  base
  proportion of any class shall not exceed the adjusted base proportion or

  adjusted  proportion,  whichever  is  appropriate,  of  the  immediately
  preceding year by more than two percent. Where the computation performed
  pursuant to paragraph (b) of this subdivision  would  otherwise  produce
  such  result, the current base proportion of such class or classes shall
  be limited to such two percent increase and the legislative body of such
  special assessing unit shall alter the current base proportion of any or
  all remaining classes so that the sum of the  current  base  proportions
  equals one.
    (k)   Notwithstanding   the   provisions  of  paragraph  (c)  of  this
  subdivision to the contrary, in a special assessing unit that is a  city
  and  for  current  base  proportions  to  be  determined in such special
  assessing  unit's  fiscal  year  two  thousand  two,  the  current  base
  proportion of any class shall not exceed the adjusted base proportion or
  adjusted  proportion,  whichever  is  appropriate,  of  the  immediately
  preceding year by more than two percent. Where the computation performed
  pursuant to paragraph (b) of this subdivision  would  otherwise  produce
  such  result, the current base proportion of such class or classes shall
  be limited to such two percent increase and the legislative body of such
  special assessing unit shall alter the current base proportion of any or
  all remaining classes so that the sum of the  current  base  proportions
  equals one.
    (l)   Notwithstanding   the   provisions  of  paragraph  (c)  of  this
  subdivision to the contrary, in a special assessing unit that is a  city
  and  for  current  base  proportions  to  be  determined in such special
  assessing unit's fiscal  year  two  thousand  three,  the  current  base
  proportion of any class shall not exceed the adjusted base proportion or
  adjusted  proportion,  whichever  is  appropriate,  of  the  immediately
  preceding year by more than two percent. Where the computation performed
  pursuant to paragraph (b) of this subdivision  would  otherwise  produce
  such  result, the current base proportion of such class or classes shall
  be limited to such two percent increase and the legislative body of such
  special assessing unit shall alter the current base proportion of any or
  all remaining classes so that the sum of the  current  base  proportions
  equals one.
    (m)   Notwithstanding   the   provisions  of  paragraph  (c)  of  this
  subdivision to the contrary, in a special assessing unit that is  not  a
  city and for current base proportions to be determined by taxes based on
  such  special assessing unit's two thousand three, two thousand four and
  two thousand five assessment rolls, the current base proportion  of  any
  class  shall  not  exceed  the  adjusted  base  proportion  or  adjusted
  proportion, whichever is appropriate, of the immediately preceding  year
  by  more  than  two percent. Where the computation performed pursuant to
  paragraph (b) of this subdivision would otherwise produce  such  result,
  the current base proportion of such class or classes shall be limited to
  such  two  percent  increase  and  the  legislative body of such special
  assessing unit shall alter the current base proportion  of  any  or  all
  remaining classes so that the sum of the current base proportions equals
  one.
    (n)   Notwithstanding   the   provisions  of  paragraph  (c)  of  this
  subdivision to the contrary, in a special assessing unit that is a  city
  and  for  current  base  proportions  to  be  determined in such special
  assessing unit's  fiscal  year  two  thousand  four,  the  current  base
  proportion of any class shall not exceed the adjusted base proportion or
  adjusted  proportion,  whichever  is  appropriate,  of  the  immediately
  preceding year by more than two percent. Where the computation performed
  pursuant to paragraph (b) of this subdivision  would  otherwise  produce
  such  result, the current base proportion of such class or classes shall
  be limited to such two percent increase and the legislative body of such

  special assessing unit shall alter the current base proportion of any or
  all remaining classes so that the sum of the  current  base  proportions
  equals one.
    (o)   Notwithstanding   the   provisions  of  paragraph  (c)  of  this
  subdivision to the contrary, in a special assessing unit which is a city
  and for current base  proportions  to  be  determined  in  such  special
  assessing  unit's  fiscal  year  two  thousand  six,  the  current  base
  proportion of any class shall not exceed the adjusted base proportion or
  adjusted  proportion,  whichever  is  appropriate,  of  the  immediately
  preceding year by more than two percent. Where the computation performed
  pursuant  to  paragraph  (b) of this subdivision would otherwise produce
  such result, the current base proportion of such class or classes  shall
  be limited to such two percent increase and the legislative body of such
  special assessing unit shall alter the current base proportion of any or
  all  remaining  classes  so that the sum of the current base proportions
  equals one.
    (p)  Notwithstanding  the  provisions  of  paragraph   (c)   of   this
  subdivision  to  the contrary, in a special assessing unit that is not a
  city and for current base proportions to be determined by taxes based on
  such special assessing unit's two  thousand  six  assessment  roll,  the
  current  base proportion of any class shall not exceed the adjusted base
  proportion or adjusted proportion,  whichever  is  appropriate,  of  the
  immediately   preceding  year  by  more  than  one  percent.  Where  the
  computation performed pursuant to  paragraph  (b)  of  this  subdivision
  would otherwise produce such result, the current base proportion of such
  class  or  classes shall be limited to such one percent increase and the
  legislative body of such special assessing unit shall alter the  current
  base  proportion  of any or all remaining classes so that the sum of the
  current base proportions equals one.
    (q)  Notwithstanding  the  provisions  of  paragraph   (c)   of   this
  subdivision to the contrary, in a special assessing unit which is a city
  and  for  current  base  proportions  to  be  determined in such special
  assessing unit's fiscal  year  two  thousand  seven,  the  current  base
  proportion of any class shall not exceed the adjusted base proportion or
  adjusted  proportion,  whichever  is  appropriate,  of  the  immediately
  preceding year by more than two percent. Where the computation performed
  pursuant to paragraph (b) of this subdivision  would  otherwise  produce
  such  result, the current base proportion of such class or classes shall
  be limited to such two percent increase and the legislative body of such
  special assessing unit shall alter the current base proportion of any or
  all remaining classes so that the sum of the  current  base  proportions
  equals one.
    * (r)   Notwithstanding  the  provisions  of  paragraph  (c)  of  this
  subdivision to the contrary, in a special assessing unit that is  not  a
  city and for current base proportions to be determined by taxes based on
  such  special  assessing  unit's two thousand seven assessment roll, the
  current base proportion of any class shall not exceed the adjusted  base
  proportion  or  adjusted  proportion,  whichever  is appropriate, of the
  immediately  preceding  year  by  more  than  one  percent.  Where   the
  computation  performed  pursuant  to  paragraph  (b) of this subdivision
  would otherwise produce such result, the current base proportion of such
  class or classes shall be limited to such one percent increase  and  the
  legislative  body of such special assessing unit shall alter the current
  base proportion of any or all remaining classes so that the sum  of  the
  current base proportions equals one.
    * NB There are 2 par (r)'s
    * (r)   Notwithstanding  the  provisions  of  paragraph  (c)  of  this
  subdivision to the contrary, in a special assessing unit which is a city

  and for current base  proportions  to  be  determined  in  such  special
  assessing  unit's  fiscal  year  two  thousand  eight,  the current base
  proportion of any class shall not exceed the adjusted base proportion or
  adjusted  proportion,  whichever  is  appropriate,  of  the  immediately
  preceding year. Where the computation performed  pursuant  to  paragraph
  (b) of this subdivision would otherwise produce such result, the current
  base  proportion  of  such  class  or classes shall be limited to a zero
  percent increase and the legislative body of such special assessing unit
  shall alter the current base proportion of any or all remaining  classes
  so that the sum of the current base proportions equals one.
    * NB There are 2 par (r)'s
    (s)   Notwithstanding   the   provisions  of  paragraph  (c)  of  this
  subdivision to the contrary, in a special assessing unit that is  not  a
  city and for current base proportions to be determined by taxes based on
  such  special  assessing  unit's two thousand eight assessment roll, the
  current base proportion of any class shall not exceed the adjusted  base
  proportion  or  adjusted  proportion,  whichever  is appropriate, of the
  immediately  preceding  year  by  more  than  one  percent.  Where   the
  computation  performed  pursuant  to  paragraph  (b) of this subdivision
  would otherwise produce such result, the current base proportion of such
  class or classes shall be limited to such one percent increase  and  the
  legislative  body of such special assessing unit shall alter the current
  base proportion of any or all remaining classes so that the sum  of  the
  current base proportions equals one.
    (t)   Notwithstanding   the   provisions  of  paragraph  (c)  of  this
  subdivision to the contrary, in a special assessing unit which is a city
  and for current base  proportions  to  be  determined  in  such  special
  assessing  unit's  fiscal  year  two  thousand  nine,  the  current base
  proportion of any class shall not exceed the adjusted base proportion or
  adjusted  proportion,  whichever  is  appropriate,  of  the  immediately
  preceding  year.   Where the computation performed pursuant to paragraph
  (b) of this subdivision would otherwise produce such result, the current
  base proportion of such class or classes shall  be  limited  to  a  zero
  percent increase and the legislative body of such special assessing unit
  shall  alter the current base proportion of any or all remaining classes
  so that the sum of the current base proportions equals one.
    * (u)  Notwithstanding  the  provisions  of  paragraph  (c)  of   this
  subdivision to the contrary, in a special assessing unit which is a city
  and  for  current  base  proportions  to  be  determined in such special
  assessing  unit's  fiscal  year  two  thousand  ten,  the  current  base
  proportion of any class shall not exceed the adjusted base proportion or
  adjusted  proportion,  whichever  is  appropriate,  of  the  immediately
  preceding year.  Where the computation performed pursuant  to  paragraph
  (b) of this subdivision would otherwise produce such result, the current
  base  proportion  of  such  class  or classes shall be limited to a zero
  percent increase and the legislative body of such special assessing unit
  shall alter the current base proportion of any or all remaining  classes
  so that the sum of the current base proportions equals one.
    * NB There are 2 par (u)'s
    * (u)   Notwithstanding  the  provisions  of  paragraph  (c)  of  this
  subdivision to the contrary, in a special assessing unit that is  not  a
  city and for current base proportions to be determined by taxes based on
  such  special  assessing  unit's  two thousand nine assessment roll, the
  current base proportion of any class shall not exceed the adjusted  base
  proportion  or  adjusted  proportion,  whichever  is appropriate, of the
  immediately  preceding  year  by  more  than  one  percent.  Where   the
  computation  performed  pursuant  to  paragraph  (b) of this subdivision
  would otherwise produce such result, the current base proportion of such

  class or classes shall be limited to such one percent increase  and  the
  legislative  body of such special assessing unit shall alter the current
  base proportion of any or all remaining classes so that the sum  of  the
  current base proportions equals one.
    * NB There are 2 par (u)'s
    * (v)   Notwithstanding  the  provisions  of  paragraph  (c)  of  this
  subdivision to the contrary, in a special assessing unit that is  not  a
  city and for current base proportions to be determined by taxes based on
  such  special  assessing  unit's  two  thousand ten assessment roll, the
  current base proportion of any class shall not exceed the adjusted  base
  proportion  or  adjusted  proportion,  whichever  is appropriate, of the
  immediately  preceding  year  by  more  than  one  percent.  Where   the
  computation  performed  pursuant  to  paragraph  (b) of this subdivision
  would otherwise produce such result, the current base proportion of such
  class or classes shall be limited to such one percent increase  and  the
  legislative  body of such special assessing unit shall alter the current
  base proportion of any or all remaining classes so that the sum  of  the
  current base proportions equals one.
    * NB There are 2 par (v)'s
    * (v)   Notwithstanding  the  provisions  of  paragraph  (c)  of  this
  subdivision to the contrary, in a special assessing unit which is a city
  and for current base  proportions  to  be  determined  in  such  special
  assessing  unit's  fiscal  year  two  thousand  eleven, the current base
  proportion of any class shall not exceed the adjusted base proportion or
  adjusted  proportion,  whichever  is  appropriate,  of  the  immediately
  preceding  year  by  more  than  two  and  a  half  percent.  Where  the
  computation performed pursuant to  paragraph  (b)  of  this  subdivision
  would otherwise produce such result, the current base proportion of such
  class  or  classes shall be limited to a two and a half percent increase
  and the legislative body of such special assessing unit shall alter  the
  current  base proportion of any or all remaining classes so that the sum
  of the current base proportions equals one.
    * NB There are 2 par (v)'s
    * (w)  Notwithstanding  the  provisions  of  paragraph  (c)  of   this
  subdivision  to  the contrary, in a special assessing unit that is not a
  city and for current base proportions to be determined by taxes based on
  such special assessing unit's two thousand eleven assessment  roll,  the
  current  base proportion of any class shall not exceed the adjusted base
  proportion or adjusted proportion,  whichever  is  appropriate,  of  the
  immediately   preceding  year  by  more  than  one  percent.  Where  the
  computation performed pursuant to  paragraph  (b)  of  this  subdivision
  would otherwise produce such result, the current base proportion of such
  class  or  classes shall be limited to such one percent increase and the
  legislative body of such special assessing unit shall alter the  current
  base  proportion  of any or all remaining classes so that the sum of the
  current base proportions equals one.
    * NB There are 2 par (w)'s
    * (w)  Notwithstanding  the  provisions  of  paragraph  (c)  of   this
  subdivision to the contrary, in a special assessing unit which is a city
  and  for  current  base  proportions  to  be  determined in such special
  assessing unit's fiscal year  two  thousand  twelve,  the  current  base
  proportion of any class shall not exceed the adjusted base proportion or
  adjusted  proportion,  whichever  is  appropriate,  of  the  immediately
  preceding  year  by  more  than  two  and  a  half  percent.  Where  the
  computation  performed  pursuant  to  paragraph  (b) of this subdivision
  would otherwise produce such result, the current base proportion of such
  class or classes shall be limited to a two and a half  percent  increase
  and  the legislative body of such special assessing unit shall alter the

  current base proportion of any or all remaining classes so that the  sum
  of the current base proportions equals one.
    * NB There are 2 par (w)'s
    * (x)   Notwithstanding  the  provisions  of  paragraph  (c)  of  this
  subdivision to the contrary, in a special assessing unit that is  not  a
  city and for current base proportions to be determined by taxes based on
  such  special  assessing unit's two thousand twelve assessment roll, the
  current base proportion of any class shall not exceed the adjusted  base
  proportion  or  adjusted  proportion,  whichever  is appropriate, of the
  immediately  preceding  year  by  more  than  one  percent.  Where   the
  computation  performed  pursuant  to  paragraph  (b) of this subdivision
  would otherwise produce such result, the current base proportion of such
  class or classes shall be limited to such one percent increase  and  the
  legislative  body of such special assessing unit shall alter the current
  base proportion of any or all remaining classes so that the sum  of  the
  current base proportions equals one.
    * NB There are 2 par (x)'s
    * (x)   Notwithstanding  the  provisions  of  paragraph  (c)  of  this
  subdivision to the contrary, in a special assessing unit which is a city
  and for current base  proportions  to  be  determined  in  such  special
  assessing  unit's  fiscal  year  two thousand thirteen, the current base
  proportion of any class shall not exceed the adjusted base proportion or
  adjusted  proportion,  whichever  is  appropriate,  of  the  immediately
  preceding  year  by  more  than  one  and  one-half  percent.  Where the
  computation performed pursuant to  paragraph  (b)  of  this  subdivision
  would otherwise produce such result, the current base proportion of such
  class or classes shall be limited to a one and one-half percent increase
  and  the legislative body of such special assessing unit shall alter the
  current base proportion of any or all remaining classes so that the  sum
  of the current base proportions equals one.
    * NB There are 2 par (x)'s
    2.  For  the  purposes  of  this  section, the base percentage and the
  current percentage of each class and for each portion shall be  computed
  pursuant to this subdivision.
    (a)  Base  percentage.  The  base  percentage  for each class for each
  assessing unit and portion thereof shall be determined as follows:
    (1) Determine the estimated market value of each class by dividing the
  taxable assessed value of the real property in each class in the special
  assessing unit and portion thereof appearing  on  the  final  assessment
  roll  completed  and  filed in nineteen hundred eighty-nine by the class
  equalization rate which was finally adopted by the commissioner for such
  roll.
    (2) Adjust the estimated market value of each  class  to  reflect  any
  change in the class designation of any parcel of real property.
    (3)  Determine  the  total  estimated  market  value  of  the  special
  assessing unit or portion thereof by summing the estimated market  value
  of each class.
    (4)  Divide  the  estimated  market  value for each class by the total
  estimated market value of the special assessing unit or portion thereof.
    Such quotient, as expressed as a percentage to at least four places to
  the right of the decimal point, shall be the  base  percentage  of  each
  class for such special assessing unit or portion thereof.
    (b) Current percentage. The current percentage for each class for each
  assessing unit and portion thereof shall be determined as follows:
    (1) Determine the estimated market value of each class by dividing the
  taxable assessed value of the real property in each class in the special
  assessing  unit  and  portion  thereof  appearing  on  the  latest final
  assessment roll for which class equalization  rates  have  been  finally

  adopted  by  the  commissioner  by the class equalization rate which was
  finally adopted by the commissioner.
    (2)  Determine  the  total  estimated  market  value  of  the  special
  assessing unit or portion thereof by summing the estimated market  value
  of each class.
    (3)  Divide  the  estimated  market  value for each class by the total
  estimated market value of the special assessing unit or portion thereof.
    Such quotient, as expressed as a percentage to at least four places to
  the right of the decimal point, shall be the current percentage of  each
  class for such special assessing unit or portion thereof.
    3. Where there was no taxable real property in a class in a portion on
  the  final  assessment  roll  completed  and  filed  in nineteen hundred
  eighty-nine, the local base proportion,  base  percentages  and  current
  percentages  for  such  portion  shall be determined as provided by this
  subdivision for each tax  levy  based  upon  an  assessment  roll  filed
  subsequent to the assessment roll on which such property first appears.
    (a)  The  local  base proportions shall be the adjusted proportions or
  adjusted  base  proportions,  whichever  are   appropriate,   determined
  pursuant  to this section for the assessment roll on which such property
  first appears.
    (b) The base percentage for each class shall be determined as follows:
    (1) For each class other than the class appearing for the first  time,
  determine  the  estimated  market value by dividing the taxable assessed
  value of the real property in the class in  the  portion  on  the  final
  assessment  roll  on  which  the  new  class first appeared by the class
  equalization rate determined for such class  in  such  portion  on  such
  roll.
    (2)  For  the  class  appearing  for  the  first  time,  determine the
  estimated market value of such class by dividing  the  taxable  assessed
  value of the real property in such class on the final assessment roll on
  which   such  class  first  appeared  by  the  class  equalization  rate
  determined for such class in the special assessing unit  on  such  final
  assessment roll.
    (3)  Determine  the  total  estimated  market  value of the portion by
  summing the estimated market value of each class.
    (4) Divide the estimated market value for  each  class  by  the  total
  estimated  market value of the portion. Such quotient, as expressed as a
  percentage to at least four places to the right of  the  decimal  point,
  shall be the base percentage of each class for such portion.
    (c)  Current  percentages shall be determined as otherwise provided by
  this section, except that until the commissioner can determine  a  class
  equalization  rate  for  the  new  class  in  such  portion,  the  class
  equalization rate for the class in the special assessing unit  shall  be
  used in lieu thereof.
    4.  Where  there  is  a  new  portion that did not appear on the final
  assessment roll completed and filed in nineteen hundred eighty-nine, the
  local base proportion, base percentages and current percentages for each
  class in such portion shall be determined  as  provided  in  subdivision
  three of this section for a new class in a portion.
    5.  Adjusted  base  proportions. No later than five days subsequent to
  the filing of the final assessment roll, the legislative  body  of  each
  special  assessing  unit  shall  adjust such current base proportions to
  reflect the addition to the assessment roll of new  property,  additions
  to  or  improvements of existing property or formerly exempt property or
  the full or partial removal from the  assessment  roll  of  property  by
  reason  of  fire, demolition, destruction or new exemption or any change
  in the class designation of any parcel of real  property  subsequent  to
  the  taxable  status  date of the latest final assessment roll for which

  class equalization rates have been finally  adopted.  The  current  base
  proportions so adjusted shall be known as the adjusted base proportions.
    6.   Upon   determination   of  the  adjusted  base  proportions,  the
  legislative body of the special assessing unit shall certify within five
  days to the commissioner, on forms prescribed by the  commissioner,  the
  adjusted  base  proportions  as computed pursuant to subdivision five of
  this section for each class applicable to the special assessing unit and
  each portion contained therein; the assessed value of  all  property  in
  each  class  for  the  special assessing unit and each portion contained
  therein; the net  change  in  assessed  value  for  each  class  on  the
  assessment  roll  resulting  from  the additions to or removals from the
  assessment roll referred to in subdivision five of this section for  the
  special  assessing  unit and each portion contained therein; and the net
  change in assessed value for each class on the assessment roll resulting
  from changes other than those referred to in subdivision  five  of  this
  section for the special assessing unit and each portion therein.
    7.  If  subsequent to and within sixty days after the certification of
  the adjusted base proportions as final by the legislative  body  of  the
  special  assessing  unit,  should  said legislative body discover that a
  mathematical error was made in the determination of  the  adjusted  base
  proportions,  the  legislative  body of the special assessing unit which
  has made such error shall redetermine such  adjusted  base  proportions,
  subject  to  the procedures set forth in this section for the review and
  certification of adjusted base proportions, prior to the levy  of  taxes
  for that fiscal year. If the redetermination cannot be made prior to the
  extension  of  taxes  for  that  fiscal year, the tax levying body shall
  adjust the tax levy for the ensuing  fiscal  year  to  account  for  the
  improper  apportionment  of  taxes  which resulted from the error in the
  determination of the adjusted base proportions.
    8.  Notwithstanding  any  other  provision  of   this   article,   the
  calculations  required by this section shall not apply to town or county
  special districts or zones of assessment.