The retirement system at the end of each fiscal year shall allow interest on the balance of the contingent reserve fund, the annuity savings fund, and the retirement reserve fund as of the beginning of said fiscal year at the regular interest rate applicable thereto to cover the interest creditable to the respective funds for the year. The amount so allowed shall be due and payable to said funds and shall be credited annually.
N.J.S. § 43:6A-35