Mich. Comp. Laws § 38.1402

Sec. 102. The percentage increase to the monthly retirement allowance payable after June 30, 1972, to a retirant or retirement allowance beneficiary, who was on the rolls for June, 1971, under section 174(1) of former Act No. 258 of the Public Acts of 1972, is continued as follows: Effective Date of Retirement Increase August 1, 1970, to July 1, 1971 1% August 1, 1969, to July 1, 1970 2% August 1, 1968, to July 1, 1969 3% August 1, 1967, to July 1, 1968 4% August 1, 1966, to July 1, 1967 5% August 1, 1965, to July 1, 1966 6% August 1, 1964, to July 1, 1965 7% August 1, 1963, to July 1, 1964 8% August 1, 1962, to July 1, 1963 9% August 1, 1961, to July 1, 1962 10% August 1, 1960, to July 1, 1961 11% August 1, 1959, to July 1, 1960 12% August 1, 1958, to July 1, 1959 13% August 1, 1957, to July 1, 1958 14% July 1, 1956, to July 1, 1957 15%