The total tax rate which may be levied without a vote of the people for the current operating expenses of The City of Springfield upon the tax list and duplicate of property assessed and listed for taxation according to value for the tax year 1966 and each year thereafter shall not exceed 3.27 mills per dollar of assessed valuation, provided that said 3.27 mills shall be reduced in each year by that number of mills, including fractional parts thereof, which are levied in the respective year by the city within the ten mill limitation imposed by Article XII, Section 2, of the Ohio Constitution, for the purpose of paying interest on and principal of obligations issued without a vote of the people.
   The limitation of this section of the Charter shall not operate as a limitation upon the power of the commission to levy taxes upon such other subjects and for such other purposes as may be lawful under the Constitution and laws of the State of Ohio, nor shall this section be deemed to be a limitation upon the power of the commission to incur indebtedness for all lawful purposes within applicable constitutional and statutory limitations.