Whenever in any school district in the State where special levies and taxes have been authorized, levied and are being collected the assessed valuation of the property shall have so increased since the authorization of the special levy as to provide an amount of taxes in excess of that contemplated at the time of the authorization of the levy or in excess of the amount collected the first year under such authorization, then, upon the written petition of the trustees of such school district approved by the county board of education and upon the petition of three fourths of the residents subject to such tax, the auditor of the county in which the school district is situate and the tax being collected shall reduce the levy for such school district to such an amount as will produce the total amount of taxes originally intended to be collected.