(a) Except as provided by Section 813.201, the board of trustees shall assess each employer whose employees are members of the retirement system a state retirement contribution in an amount equal to 0.5 percent of the employer's total payroll, as determined by the General Appropriations Act.
(b) The board of trustees shall deposit the state retirement contribution to the credit of the trust fund established by Section 815.310 to be used for the purposes specified by Section 815.103.