A city levies a property tax that is restricted for future period payments of principal and interest on outstanding debt. The tax receipts are recorded in a debt service fund and are invested in interest-and dividend-earning securities. Hence, the amount of the taxes levied is less than the ultimate amount to be paid. Should the taxes received in a current period be reported as deferred tax revenues and recognized as revenue only at the start of the future periods in which the payments of interest and principal are actually due?