An annuitant shall first be entitled to an initial increase under this Section on the January 1 next following the first anniversary of retirement, or January 1 of the year next following attainment of age 61, whichever is later. At such time, the system shall pay an initial increase determined as follows:
However, the initial annual increase calculated under this Section for the recipient of a disability retirement annuity granted under Section 16-149.2 shall be reduced by an amount equal to the total of all increases in that annuity received under Section 16-149.5 (but not exceeding 100% of the amount of the initial increase otherwise provided under this Section).
Following the initial increase, automatic annual increases in annuity shall be payable on each January 1 thereafter during the lifetime of the annuitant, determined as a percentage of the originally granted retirement annuity or disability retirement annuity for increases granted prior to January 1, 1990, and calculated as a percentage of the total amount of annuity, including previous increases under this Section, for increases granted on or after January 1, 1990, as follows: 1.5% for periods prior to January 1, 1972, 2% for periods after December 31, 1971 and prior to January 1, 1978, and 3% for periods after December 31, 1977.
On January 1, 1987, any annuitant whose retirement annuity began on or before January 1, 1977, shall receive an increase in the monthly retirement annuity equal to 8 per year of creditable service times the number of years that have elapsed since the annuity began.
40 ILCS 5/16-133.1