The assessments of each member insurer shall be in the proportion that the net direct written premiums of the member insurer for the preceding calendar year on the kinds of insurance in the account bears to the net direct written premiums of all member insurers for the preceding calendar year on the kinds of insurance in the account. The assessment is due not less than thirty days after prior written notice to the member insurer and shall accrue interest at ten percent per annum on and after the due date.
SDCL 58-29A-77