f. Commencing September first, two thousand, all retired members who have retired prior to the calendar year nineteen hundred ninety-seven and who meet the eligibility criteria set forth in subdivision a of this section shall be paid an adjusted benefit in monthly installments on the basis provided for in this subdivision. Said adjusted benefit shall be equal to a percentage of the change in consumer price index (all urban consumers, CPI-U, U.S. city average, all items, 1982-84=100), published by the United States bureau of labor statistics, measured from the year of retirement through calendar year nineteen hundred ninety-seven according to the following schedule: Year of retirement Percentage
1968 through 1996 50%
1966 and 1967 55%
1965 60%
1964 65%
1963 70%
1962 80%
1961 90%
prior to 1961 100% Said adjusted benefit shall be computed on a base benefit amount not to exceed eighteen thousand dollars of the retirement allowance otherwise payable, computed without optional modification. Any benefit received pursuant to this subdivision shall be in lieu of any benefit received pursuant to section three hundred seventy-eight of this title.