(a) The city council or the board of trustees of the municipality shall annually levy a tax upon all the taxable property of the municipality at the rate on the dollar which will produce an amount which, when added to the deductions from the salaries or wages of firefighters and revenues available from other sources, will equal a sum sufficient to meet the annual actuarial requirements of the pension fund, as determined by an enrolled actuary employed by the Illinois Department of Insurance or by an enrolled actuary retained by the pension fund or municipality. For the purposes of this Section, the annual actuarial requirements of the pension fund are equal to (1) the normal cost of the pension fund, or 17.5% of the salaries and wages to be paid to firefighters for the year involved, whichever is greater, plus (2) an annual amount sufficient to bring the total assets of the pension fund up to 90% of the total actuarial liabilities of the pension fund by the end of municipal fiscal year 2040, as annually updated and determined by an enrolled actuary employed by the Illinois Department of Insurance or by an enrolled actuary retained by the pension fund or the municipality. In making these determinations, the required minimum employer contribution shall be calculated each year as a level percentage of payroll over the years remaining up to and including fiscal year 2040 and shall be determined under the projected unit credit actuarial cost method. The amount to be applied towards the amortization of the unfunded accrued liability in any year shall not be less than the annual amount required to amortize the unfunded accrued liability, including interest, as a level percentage of payroll over the number of years remaining in the 40-year amortization period.
     (a-2) A municipality that has established a pension fund under this Article and that employs a full-time firefighter, as defined in Section 4-106, shall be deemed a primary employer with respect to that full-time firefighter. Any municipality of 5,000 or more inhabitants that employs or enrolls a firefighter while that firefighter continues to earn service credit as a participant in a primary employer’s pension fund under this Article shall be deemed a secondary employer and such employees shall be deemed to be secondary employee firefighters. To ensure that the primary employer’s pension fund under this Article is aware of additional liabilities and risks to which firefighters are exposed when performing work as firefighters for secondary employers, a secondary employer shall annually prepare a report accounting for all hours worked by and wages and salaries paid to the secondary employee firefighters it receives services from or employs for each fiscal year in which such firefighters are employed and transmit a certified copy of that report to the primary employer’s pension fund, the Department of Insurance, and the secondary employee firefighter no later than 30 days after the end of any fiscal year in which wages were paid to the secondary employee firefighters.
     Nothing in this Section shall be construed to allow a secondary employee to qualify for benefits or creditable service for employment as a firefighter for a secondary employer.
     (a-5) For purposes of determining the required employer contribution to a pension fund, the value of the pension fund’s assets shall be equal to the actuarial value of the pension fund’s assets, which shall be calculated as follows:
         (1) On March 30, 2011, the actuarial value of a