Upon the basis of an investigation or valuation, the Retirement Board shall adopt appropriate interest rates. The interest rate applied to member accounts shall be at least four percent per annum and shall not exceed the actuarial assumption for return on assets.
The Retirement Board, by means of a dividend payment method, may distribute annually to those persons receiving allowances from the Retirement Systemare not subject to change when the salary rates of active members change and which at the close of the next preceding fiscal year had been in effect for at least one yearpart or all of the net interest earnings in excess of the assumed earnings during the preceding fiscal year on the Retirement Fund except earnings upon the accumulated contributions of active members; provided, however, that no such distribution shall be made of that part of said excess interest earnings as is required to maintain the contingency reserve against adverse mortality at an amount equal to two percent of the total assets of the Retirement System at the close of the next preceding fiscal year.
