Regular interest shall be credited annually to the mean amount of the employee reserve account for the preceding year. This credit shall be made annually from interest and other earnings on the invested assets of this system. Any additional amount required to meet the regular interest on the funds of this system shall be charged to the employer's accumulation account, and any excess of earnings over such regular interest required shall be credited to the employer's accumulation account. Regular interest shall mean the percentage rate of interest compounded annually as determined by the Board of Trustees of the Public Employees' Retirement System.
Once interest is credited it shall be added to the sum of all amounts deducted from the compensation of a member and shall be included in determining his total contributions.