(1) There is created a fund to be known as the federal riot reinsurance reimbursement fund, hereinafter referred to as the fund, which shall be operated under the joint control of the state treasurer and the commissioner of insurance. The fund shall consist of all payments made to the fund by insurers in accordance with the provisions of this section. The state treasurer shall enforce the collection of the assessments provided hereunder as any other obligation due the state.

  (2) The fund shall reimburse the secretary of the department of housing and urban development, hereinafter referred to as the secretary, in an amount up to 5% of the aggregate property insurance premiums earned in this state during the calendar year immediately preceding the calendar year, with respect to which the secretary paid losses on lines of insurance reinsured by him in this state during that year and for which he claims reimbursement from the fund in accordance with section 1223 of the housing and urban development act of 1968, Public Law 90-448, 90th congress, August 1, 1968, hereinafter referred to as the act.

  (3) Whenever the secretary, in accordance with the act, shall present to the state a request for reimbursement under the act, the fund shall immediately assess all insurers which, during the calendar year with respect to which reimbursement is requested by the secretary, were reinsured under the act. The amount of each insurer‘s assessment shall be calculated by multiplying the amount of the reimbursement requested by the secretary by a fraction the numerator of which is the insurer’s premiums actually reinsured in this state with the secretary in that calendar year and the denominator of which is the aggregate of such reinsured premiums for all insurers.

  (4) The fund shall reimburse the secretary, up to amounts actually collected by it, upon drafts or vouchers duly authorized by the state treasurer with the approval of the commissioner of insurance.

  (5) If any insurer fails, by reason of insolvency, to pay any assessment, the fund shall cause the reimbursement ratios, computed under subsection (3) to be immediately recalculated, excluding therefrom the insolvent insurer, so that, its assessment is in effect, assumed and redistributed among the remaining insurers.

  (6) If the secretary determines that the provisions of this section are not sufficient to meet the requirements of section 1223 of the act, the fund shall assess, with respect to the calendar year in which the determination is made and for each calendar year thereafter, against each insurer, which during the applicable calendar year obtained reinsurance with the secretary on premiums earned in this state, an amount equal to the maximum for which the fund would be liable to the secretary for that calendar year multiplied by a fraction the numerator of which is the insurer’s premiums actually reinsured in the state with the secretary during that calendar year and the denominator of which is the aggregate of such reinsured premiums for all insurers. As soon as practicable after the close of a calendar year, the fund, in accordance with the formula provided in subsection (3), shall calculate the actual liability of each insurer for reimbursement to the secretary for that calendar year. The difference between the actual liability so calculated and the amount previously assessed and paid with respect to that calendar year under this section shall be credited by the fund toward the assessment against each such insurer for the subsequent calendar year.

  (7) In the event that the provisions of this section and the assessments made thereunder are no longer needed in order to effectuate the program for which they were intended, the amounts remaining in the fund shall be returned to the insurers in proportion to the amount which they paid.

  (8) This section shall be retroactive to August 1, 1968.