Mich. Comp. Laws § 38.1638

Sec. 38. The supplement to the retirement allowance payable under section 8c of former Act No. 251 of the Public Acts of 1935, described as follows, is retained: Effective Date of Retirement Percent Supplemented 10-1-76 10-1-77 July 1, 1975 to June 30, 1976 1 1 July 1, 1974 to June 30, 1975 2 2 July 1, 1973 to June 30, 1974 3 3 July 1, 1972 to June 30, 1973 4 4 July 1, 1971 to June 30, 1972 5 5 July 1, 1970 to June 30, 1971 6 6 July 1, 1969 to June 30, 1970 7 7 July 1, 1968 to June 30, 1969 8 8 Before July 1, 1968 8 8