To calculate benefits pursuant to §§ 3-12C-805, 3-12C-901, and 3-12C-1004 before July 1, 2004, the system shall use the member's highest annual compensation earned by the member during any one of the last three years of contributory service, so long as it is not more than one hundred fifteen percent of the member's final compensation calculated as of the date of the member's death or disability.
SDCL 3-12C-707