Indiana Code Title 5. State and Local Administration § 5-10.2-5-6

Sec. 6. (a) The monthly benefit (B) payable on and after July 1, 1977, to a member, or a survivor or beneficiary of a member, who retired or was disabled before July 2, 1972, shall be increased by an amount equal to the benefit payable (J) in June 1977 times one-half percent ( 1/2 %) times the number of years (y) from the member's date of retirement or disability through June 1977.

Expressed mathematically:  B = (1 + .005_y)J

This subsection does not apply to persons receiving disability benefits under IC 5-10.4-5-2.

(b) As a cost of living increase, the retirement, disability, and survivor benefit payable on and after July 1, 1978, to a member, or a beneficiary or survivor of a member, who retired before July 2, 1977, shall be increased by three percent (3%).  This subsection does not apply to benefits payable in a lump sum.