The taxes assessed in the general city tax roll, for each fiscal year, shall be due and payable on the first day of July of each year, and may be paid at any time on or before the last day of August of the same year, with an administration fee of one percent (1%). An additional charge of three and three-fourths (3.75%) percent shall be added to all unpaid general city taxes on the first day of September of the same year, and thereafter an additional charge of three-fourths of one percent (.75%) shall be made and added to all such unpaid taxes on the first day of each month during which such taxes shall remain unpaid, until return thereof, together with such accrued penalties or charges, shall be made to the county treasurer. And the said county treasurer, or auditor general of the State, as the case may be, shall account to the City for all such accrued penalties of charges.