For any generational member, the term, accumulated contributions, means the sum of:
(1) All contributions made by the member;
(2) Eighty-five percent of the contributions made by the member's employer if the member has three years or more of contributory service or noncontributory service, or fifty percent of the contributions made by the employer if the member has less than three years of contributory service or noncontributory service;
(3) Member credited service purchases pursuant to §§ 3-12C-504, 3-12C-509, and 3-12C-511; and
(4) The effective rate of interest on the sum of subdivisions (1), (2), and (3).