Any increase in a retired member's benefit as a result of credited service related to years of noncontributory service, or fractions thereof, earned by a member from July 1, 1967, to June 30, 1974, inclusive, but not credited under the South Dakota public employee retirement system because of the age and service restrictions established under the system shall be prospective only from July 1, 1997.
SDCL 3-12C-505