Accounts shall be kept for each public utility owned or operated by the city, in such manner as to show the true and complete financial results of such city ownership and operation, including all assets, appropriately subdivided into different classes; all liabilities subdivided by classes; depreciation reserve, other reserves and surplus; also all revenue, operating expenses including depreciation, interest payments, rental, and other disposition of annual income. The accounts shall show the actual capital cost to the city of each public utility owned, also the cost of all extensions, additions, and improvements, and the source of the funds expended for such capital purposes. They shall show as nearly as possible the cost of any service furnished to or rendered by any such utility to any other city or governmental department. The commission shall annually cause to be made and published a report showing the financial results of such city ownership and operation, giving the information specified in this section or such data as the city council shall deem expedient.