The annual audit report shall set forth, insofar as possible, the financial position and results of financial operations for each fund or group of accounts of the municipality. When the accrual method is selected for the annual audit report, such report shall be in accordance with generally accepted accounting principles. The annual audit report shall also include the professional opinion of the accountant with respect to the financial statements, or, if an opinion cannot be expressed, a declaration that the accountant is unable to express such an opinion with an explanation of the reasons why he or she cannot do so.