Transactions pertaining to the ownership and operation by the city of each public utility shall be recorded in a separate group of accounts under an appropriate fund caption, which accounts shall be classified in accordance with generally accepted utility accounting practice. Charges for all service furnished to, or rendered by, other city departments or agencies, shall be recorded. An annual report shall be prepared to show fairly the financial position of the utility and the results of its operation, which report shall be available for inspection at the office of the Clerk.