The said board of directors shall make, on or before the second Monday in June, an annual report to the city council stating the condition of their trust on the first day of May of that year, the various sums of money received from the park fund and other sources, and how much moneys have been expended and for what purposes, with such other statistics, information and suggestions as they may deem of general interest. All such portions of such report as relate to the receipt and expenditure of money shall be verified by affidavit.