a grant under this subsection shall be equal to the amount obtained by multiplying the amount available to the State under paragraph (6)(B) by the quotient obtained by dividing— (i) the voting age population of the State (as reported in the most recent decennial census) who would cast their ballots in a Federal election using voting systems that are operated by the election agency (under current State law) and that would not be eligible for purchase under subsection (f)