The board of trustees shall keep in convenient form such data as shall be necessary for actuarial valuation of the various funds of the retirement system and for checking the experience of the system.
It shall keep a record of all of its proceedings which shall be open to public inspection. It shall publish annually a report showing the fiscal transactions of the retirement system for the preceding fiscal year, the amount of the accumulated cash and securities of the system, and the last balance sheet showing the financial condition of the system by means of an actuarial valuation of the assets and liabilities thereof.