Annually for the first two full fiscal years after November 16, 1990, the Secretary shall pay for use by units of local government within the recreation area an amount equal to the difference between the amounts payable for such purposes pursuant to the Act of May 23, 1908 (chapter 193;
35 Stat. 251;
16 U.S.C.
500) and the average amount paid for such purpose under such Act during the five fiscal years preceding November 16, 1990. The amount payable under this subsection shall be reduced by 10 percent annually thereafter for each succeeding fiscal year until the amount payable shall be reduced 100 percent by the end of the twelfth fiscal year after November 16, 1990. This subsection shall expire 11 years after the first payment pursuant to this subsection.