The tax for bond interest for a Class IV school district shall in no one year exceed such amount as will, with the balance on hand in such fund, be sufficient to pay the bond interest as it becomes due. The tax for the bond sinking fund shall not exceed a sum sufficient to pay the principal of such bonds as it becomes due or to pay each year such number of the bonds as will retire them all at or before their maturity. The amount of tax levied for the retirement plan fund and for general school purposes shall be without restriction, except that the aggregate school tax levy for all purposes shall not in any one year exceed such rate as shall be necessary to provide the sums reported in the estimate returned in accordance with section 79-1085. The amount of tax levied for the building and equipment fund shall not in any one year exceed fourteen cents on each one hundred dollars within the limits provided in section 77-3442.