It shall be the duty of said board to keep a record of its proceedings and of its receipts, expenditures and operations, and shall annually render a full and complete itemized report, stating the condition of their trust, together with such other suggestions as they may deem of general interest to the mayor and common council of said cities and the county commission of said counties; provided, said board shall render reports concerning receipts, expenditures, operations, etc., whenever called for by the common council of said cities or the county commission of said counties.