53 Pa. Stat. § 761
The several cities of this Commonwealth, incorporated by general or special laws, shall establish by ordinance a police retirement fund to be maintained by an equal and proportionate monthly charge against each member of the police force which shall not exceed annually three and one-half per centum of the pay of such member and by annual appropriations made by the city, which fund shall be under the direction of councils or committed to the direction of such officers of the city as may be designated by councils, and applied under such regulations as councils may by ordinance prescribe for the benefit of such members of the police force as shall receive honorable discharge therefrom by reason of age or disability and the families of such as may be injured or killed in the service, but such retirement allowances as shall be made to those who are retired by reason of the disabilities or age shall be in conformity with a uniform scale.
The annual appropriation made by the city each year shall be sufficient, when added to the contributions made by members of the police force during such year and income from investments, to pay in full the retirement allowances payable during such year.
Such ordinance may prescribe a minimum period of continuous service, not less than twenty years and a minimum age of fifty years, after which members of the force shall be eligible for retirement from active duty and such members as are retired shall be subject to service from time to time as a police reserve until unfitted for such service, when they may be finally discharged by reason of age or disability.
Payments made under the provisions of this section shall not be a charge on any other fund in the treasury of the city or under its control save the police retirement fund herein provided for. The basis of the apportionment of the retirement allowance shall be determined by the rate of the monthly pay of the member at the date of death, honorable discharge, or retirement, and shall not exceed in any year one-half the annual pay of such member computed at such monthly rate, unless the retirement allowance so determined is less than one hundred twenty-five dollars ($125.00) per month, in which case the minimum retirement allowance of any member presently or hereafter entitled to a retirement allowance may be increased to one hundred twenty-five dollars ($125.00) per month.
53 P.S. § 761