S.C. Code § 9-1-1740
Effective July 1, 1967, the monthly benefits, inclusive of the supplemental allowances payable under the provisions of Sections 9-1-1910, 9-1-1920 and 9-1-1930, for persons who commenced receiving benefits from the System prior to July 1, 1966, shall be increased as follows:
If benefits commenced July 1, 1965 to June 30, 1966, the increase shall be five percent. An additional one percent shall be added for each preceding fiscal year in which benefits commenced until July 1, 1945, at which time the increase shall be twenty-five percent.
The minimum increase pursuant to this section, inclusive of the increase in the supplemental allowances, shall be five dollars per month. However, if an optional benefit has been elected, the minimum shall be reduced actuarially as determined by the Board, and shall be applicable to the retired member or his designated beneficiary under the option elected.
S.C. Code § 9-1-1740