(b) The General Assembly shall, by law, provide for procedures to be followed with respect to adjusting ad valorem taxes or millage pledged for bonded indebtedness purposes, to assure that the adjusted or rolled-back rate of tax or millage levied for bonded indebtedness purposes will, at all times, provide a level of income sufficient to meet the current requirements of all principal, interest, paying agent fees, reserves, and other requirements of the bond indenture.