40 ILCS 5/22-901.1

Tabular listings of assumed rates of decrement representing such factors as death, disability, separation from service, and ages of retirement, according to sex and ages of members of the retirement systems, together with mathematical functions derived from rates of probability combined with an interest discount factor that may be adopted by a board of trustees or retirement board upon recommendation of a qualified actuary based upon the experience of the pension fund or retirement system.