For purposes of §§ 58-15-15.4 to 58-15-15.12, inclusive, the "published monthly average" means Moody's corporate bond yield average--monthly average corporates, as published by Moody's investors service, incorporated, by yearly order of the director, or in the event that Moody's corporate bond yield average--monthly average corporates is no longer published, a substantially similar average, established by rule promulgated by the director.
SDCL 58-15-15.5