For the purpose of providing funds to enable the authority to pay, at their respective maturities, the principal of and interest on any bonds issued by it under the provisions of this article and to accomplish the objects of this article, there is hereby irrevocably pledged to such purpose and there is hereby appropriated so much as may be necessary for such purpose of the receipts from the tax levied by Sections 40-25-2 and 40-25-41 and distributed in accordance with subparagraph (1) b. 1. i. of Section 40-25-23. All moneys hereby appropriated and pledged shall constitute a sinking fund for the purpose of paying the principal of and the interest on the bonds authorized by this article.
Ala. Code § 41-10-30 (1975)