After the resolution providing for the issuance of the bonds has been adopted, it shall be the duty of the County Clerk annually to extend taxes against all the taxable property situated in said County sufficient to pay the principal of and interest on such bonds as they mature. The rate at which such taxes shall be extended shall be in addition to the maximum rate now or hereafter authorized to be levied and extended for General County Purposes, and shall be in addition to the rates extended for any and all taxes now or hereafter authorized or permitted to be levied or extended for county purposes in excess of the maximum rate for general county purposes now or hereafter permitted by law; such tax shall not be subject to any limitation as to amount or rate except the constitutional limitation of 75? per $100.00 valuation.