On and after December 31, 1971, all persons who retired and were eligible to receive a pension that was payable prior to July 1, 1968, pursuant to section 3309.36 or 3309.40 or former section 3309.38 of the Revised Code, or in the event of the death of such persons, the person designated by the deceased to receive payments under section 3309.46 of the Revised Code, shall receive an additional monthly payment of two dollars for each year between the member's effective date of retirement or disability and December 31, 1971, or an additional fifty dollars, whichever is less.
R.C. § 3309.376