(1) Effective October 1, 1987, the monthly retirement allowance payable to a retirant or retirement allowance beneficiary whose retirement allowance effective date was before October 1, 1986, as recalculated pursuant to section 19(2) and 20(6), is supplemented as follows:

Effective Date of Retirement	Percent of Increase
October 1, 1985 to September 30, 1986	4
October 1, 1984 to September 30, 1985	5
October 1, 1983 to September 30, 1984	6
October 1, 1982 to September 30, 1983	7
October 1, 1981 to September 30, 1982	8
October 1, 1980 to September 30, 1981	9
October 1, 1979 to September 30, 1980	10
October 1, 1978 to September 30, 1979	11
October 1, 1977 to September 30, 1978	12
October 1, 1976 to September 30, 1977	13
October 1, 1975 to September 30, 1976	14
October 1, 1974 to September 30, 1975	15
October 1, 1973 to September 30, 1974	16
October 1, 1972 to September 30, 1973	17
October 1, 1971 to September 30, 1972	18
October 1, 1970 to September 30, 1971	19
October 1, 1969 to September 30, 1970	20
October 1, 1968 to September 30, 1969	21
October 1, 1967 to September 30, 1968	22
October 1, 1966 to September 30, 1967	23
October 1, 1965 to September 30, 1966	24
October 1, 1964 to September 30, 1965	25
October 1, 1963 to September 30, 1964	26
October 1, 1962 to September 30, 1963	27
October 1, 1961 to September 30, 1962	28
October 1, 1960 to September 30, 1961	29
Before October 1, 1960	30

(2) The recalculated retirement allowance shall be the basis on which future adjustments to the allowance are calculated.

    (3) The supplement provided by this section shall be calculated pursuant to subsection (1), shall be based on the amount of retirement allowance that would have been paid without application of section 20(2) if the member made the election permitted under section 20(2), and shall be paid by January 1, 1988. The retirement allowance of a retirant who dies before January 1, 1988 and who has not nominated a retirement allowance beneficiary pursuant to section 31 shall not be supplemented pursuant to this section.

    (4) In the case of a member who retired pursuant to section 19a, the calculation of the supplement provided by this section shall not include the benefits received under section 19a(2) or (3).