It is hereby expressly provided and pledged for the benefit of the purchasers, owners and holders of said bonds that five cents ($0.05) of the tax on each package of cigarettes levied by Section 1, Chapter 47, 1968 Oklahoma Session Laws,¹ constituting the remainder of revenue available for the revenues lawfully levied and collected by the State of Oklahoma on the sale of cigarettes not already committed to other obligations of the State of Oklahoma, or so much as may be necessary, shall be devoted irrevocably to the payment and discharge of the interest on, and the principal of, the bonds issued hereunder as the same become due, and said revenues shall be, and hereby are, irrevocably pledged for such purposes.