40 ILCS 5/9-126

An employee who attains age 60 or more but less than age 65 in service, upon withdrawal, shall be entitled to annuity as follows: 1. Present Employee--Age and service and prior service annuities provided from the total sum accumulated to his credit for such annuities on the date of withdrawal, computed as of his age on such date of withdrawal. 2. Future Entrant--Age and service annuity provided from the total sum accumulated to his credit for such annuity on the date of withdrawal, computed as of his age on such date of withdrawal.