Indiana Code Title 5. State and Local Administration § 5-10.2-5-13

(1) before July 2, 1966, shall be increased by four percent (4%);

(2) after July 1, 1966, and before July 2, 1971, shall be increased by three percent (3%);  and

(3) after July 1, 1971, and before July 2, 1981, shall be increased by two percent (2%).

(1) shall be based upon the date of the member's initial retirement or disability;

(2) do not apply to benefits payable in a lump sum;  and

(3) are in addition to any other increase provided by law.