For all liability policies written during the three years immediately preceding the date as of which the statement is made, the reserve required by § 58-26-31 shall be calculated in accordance with the Annual Statement Instructions Manual prescribed by the National Association of Insurance Commissioners as adopted by rule by the director pursuant to chapter 1-26. But in any event, the reserve may not be less than the determined and estimated unpaid claims under policies written during the three-year period. For all liability policies written more than three years prior to the date as of which the statement is made, the reserves required by § 58-26-31 shall be determined and estimated unpaid claims.
SDCL 58-26-34