Mich. Comp. Laws § 38.1403

Sec. 103. (1) The percentage increase to the monthly retirement allowance payable to a retirant or retirement allowance beneficiary under section 27d of chapter I or section 25a of chapter II of former Act No. 136 of the Public Acts of 1945, is continued as provided in this section. (2) After June 30, 1974, the monthly retirement allowance payable to a retirant or retirement allowance beneficiary who was on the rolls for June, 1973, is supplemented as follows: Effective Date of Retirement Increase July 1, 1972, to June 30, 1973 1% July 1, 1971, to June 30, 1972 2% July 1, 1970, to June 30, 1971 3% July 1, 1969, to June 30, 1970 4% July 1, 1968, to June 30, 1969 5% July 1, 1967, to June 30, 1968 6% July 1, 1966, to June 30, 1967 7% July 1, 1965, to June 30, 1966 8% July 1, 1964, to June 30, 1965 9% July 1, 1963, to June 30, 1964 10% July 1, 1962, to June 30, 1963 11% July 1, 1961, to June 30, 1962 12% July 1, 1960, to June 30, 1961 13% July 1, 1959, to June 30, 1960 14% July 1, 1958, to June 30, 1959 15% July 1, 1957, to June 30, 1958 16% July 1, 1956, to June 30, 1957 17%