(a) The board of trustees shall designate an actuary.
(b) The actuary must be thoroughly qualified to be the technical adviser of the board of trustees on matters concerning operation of the funds of the retirement system.
(c) At least once every four years, the actuary, under the direction of the board of trustees, shall:
(1) make an actuarial investigation of the mortality, service, and compensation experience of the members and beneficiaries of the retirement system; and
(2) make a valuation of the assets and liabilities of the retirement system's funds.
(d) On the basis of tables adopted by the board of trustees under Section 815.105, the actuary shall make a valuation of the assets and liabilities of the retirement system's funds annually.
(e) The actuary shall perform such other duties as are required by the board of trustees.