In general
The Secretary shall prescribe regulations for reducing the minimum participation rate otherwise required by this section for a fiscal year by the number of percentage points equal to the number of percentage points (if any) by which—
(i)#
the average monthly number of families receiving assistance during the immediately preceding fiscal year under the State program funded under this part or any other State program funded with qualified State expenditures (as defined in section 609(a)(7)(B)(i) of this title ) is less than
(ii)#
the average monthly number of families that received assistance under any State program referred to in clause (i) during fiscal year 2015.
The minimum participation rate shall not be reduced to the extent that the Secretary determines that the reduction in the number of families receiving such assistance is required by Federal law.