The officials now or hereafter charged by law with the duty of levying general (ad valorem) taxes for the payment of bonds and interest shall, in the manner provided by law, make an annual levy sufficient to meet the annual or semiannual payments of principal and interest on the bonds maturing or the mandatory sinking fund payments as in this article provided. Nothing herein contained shall be so construed as to prevent the municipal corporation from applying any other funds that may be in the treasury or investment income actually received from sinking fund investments and available for that purpose to the payment of the interest on or the principal of or any prior redemption premium in connection with such bonds as the same become due; and upon such payments, the levy or levies herein provided may thereupon to that extent be diminished.
NMS § 6-15-4