The board shall apply the contributions of the county or district to its obligations under the system in the order and amounts as follows:
First, in an amount equal during each fiscal year to the liability accruing to the county or district because of service rendered during such year and on account of service and disability pensions, in an amount determined by the actuarial valuation as interpreted by the actuary.
Second, in an amount equal during each fiscal year to the payments made from contributions by the county or district during the year for death benefits.
Third, the balance of such contributions on the liabilities accrued on account of prior service benefits.
Ca. Gov. Code § 31587