Any city having established a policeman’s retirement fund may levy a tax of not to exceed eight hundredths per cent (.08%) of market value for assessment purposes of property within the corporate limits of the city, except where pursuant to section 50-1525, Idaho Code, it is found that the levy is not sufficient to meet the fund’s future liability, in which case the levy may be increased to provide for the actuarial soundness of the fund. Said taxes shall be placed by the city treasurer in a fund to be known as the "policeman’s retirement fund." Sums certain, as determined by the governing body, not to exceed eight per cent (8%) per month, may be deducted from the salary of each police officer and placed in said "policeman’s retirement fund" by the treasurer. When all claims against the fund have been satisfied, the authority to levy according to this section shall terminate.