S.C. Code § 9-1-1070
The rate per cent determined immediately after the first valuation by the actuary engaged by the Board as the rate per cent of the total annual earnable compensation of all members which is equivalent to four per cent of the amount of the total employer annuity liability on account of all members and beneficiaries which is not dischargeable by the aforesaid normal contribution made on account of such members during the remainder of their active service shall be known as the "accrued liability contribution rate." Such rate shall be increased on the basis of subsequent valuations if benefits are increased over those included in the valuation on the basis of which the original accrued liability contribution rate was determined. Upon certification by the actuary engaged by the Board that the accrued liability contribution rate may be reduced without impairing the System, the Board may cause the accrued liability contribution rate to be reduced.
S.C. Code § 9-1-1070