In addition to the fees required to be paid in Kan. Stat. Ann. § 12-2623, and amendments thereto, and as a condition precedent to the continuation of the certificate of authority provided in this act, all group-funded pools shall pay not later than 90 days after the end of each calendar year a tax upon the annual Kansas gross premium collected by the pool at the rate of 1% per annum applied to the collective premium relating to all Kansas members of the pool for the preceding calendar year. In the computation of the tax, all pools shall be entitled to deduct any annual Kansas gross premiums returned on account of cancellation or dividends returned to members of such pools or expenditures used for the purchase of specific and aggregate excess insurance, as provided in Kan. Stat. Ann. § 12-2618(h), and amendments thereto.