An employee who retires on annuity after December 31, 1959 and before January 1, 1987, but before age 60, shall receive such increases beginning in January of the year after the year in which he attains age 60. An employee who retires from service on or after January 1, 1987 shall, upon the first annuity payment date following the first anniversary of the date of retirement, or upon the first annuity payment date following attainment of age 60, whichever occurs later, have his then fixed and payable monthly annuity increased by 3%, and such annuity shall be increased by an additional 3% of the original fixed annuity on the same date each year thereafter. Beginning in January of 1999, such increases shall be at the rate of 3% of the currently payable monthly annuity, including any increases previously granted under this Article.
Beginning with January, 1960, each employee shall contribute by means of salary deductions 1/2 of 1% of each salary payment, concurrently with and in addition to the employee contributions otherwise made for annuity purposes.
Each such additional contribution shall be credited to an account in the prior service annuity reserve, to be used, together with city contributions, to defray the cost of the specified annuity increments. Any balance in such account at the beginning of each calendar year shall be credited with interest at the rate of 3% per annum.
Such additional employee contributions are not refundable, except to an employee who withdraws and applies for refund under this Article, and in cases where a term annuity becomes payable. In such cases his contributions shall be refunded, without interest, and charged to such account in the prior service annuity reserve.
40 ILCS 5/8-137