School district taxes must be levied by the governing body of each school district on or before the tenth day of August of each year. The governing body of the school district may increase or decrease its tax levy and budget for the current fiscal year on or before the tenth day of October of each year but the certification must be filed with the county auditor within the time limitations under section 57-15-31.1. Taxes for school district purposes must be based upon an itemized budget statement which must show the complete expenditure program of the district for the current fiscal year and the sources of the revenue from which it is to be financed. The school board of each public school district, in levying taxes, is limited by the amount necessary to be raised for the purpose of meeting the appropriations included in the school budget of the current fiscal year, and the sum necessary to be provided as an interim fund, together with a tax sufficient in amount to pay the interest on the bonded debt of the district and to provide a sinking fund to pay and discharge the principal thereof at maturity.