All bonds issued under or recognized by § 44a of Article IV of the previous constitution, which remain unpaid shall be valid obligations of the state and shall be paid according to the tenor thereof. On or before the first day of July of each year the state auditor shall determine the rate of taxation for that year necessary to raise the amount of money needed to pay the principal and interest maturing in the next succeeding year, taking into consideration available funds, delinquencies and the cost of collection. The auditor shall annually certify the rate of taxation so determined to the officer in each county whose duty it is to make up and certify the tax books wherein are extended the state taxes. Said officers shall extend upon the tax books the taxes to be collected and certify the same to the collector of revenue of their respective counties, who shall collect such taxes at the same time and in the same manner and by the same means as are provided by law for the collection of state and county taxes, and pay the same into the state treasury.