PUBLIC SCHOOL CONTRIBUTION.

(a) Each state fiscal year, each public school shall contribute to the fund the amount prescribed by the General Appropriations Act, which may not be less than 0.25 percent or greater than 0.75 percent of the salary of each active employee of the public school. The public school shall make the contributions on a monthly basis and as otherwise prescribed by the trustee.

(b) Each state fiscal year, each employer who reports to the retirement system under Section 824.6022, Government Code, the employment of a retiree who is enrolled in and receiving coverage under the group program shall contribute to the fund an amount established by the trustee. In determining the amount to be contributed by the employer under this subsection, the trustee shall consider the amount a retiree is required to pay for the retiree and any enrolled dependents to participate in the group program and the cost of all retirees' and enrolled dependents' participation in the group program. If more than one employer reports the retiree to the retirement system during a month, the amount of the contribution required by this subsection shall be prorated among the employers. The amounts required to be paid under this subsection are not required to be paid by a reporting employer for a retiree who retired from the retirement system before September 1, 2005.