As of $2021,$ which class of mutual funds had the largest amount of assets invested?

$\backslash$table$[[,\backslash$table$[[$Assets $($$$],[$billion$)]],\backslash$table$[[\%$ of Tota$],[$Assets$]],\backslash$table$[[$umber of$],[$Funds$]]],[$Equity funds$],[$Capital appreciation focus,$$3,021,12\mathrm{.}6\%,1,234],[$World$/$international$,3,205,13\mathrm{.}4\%,1,459],[$Total return,$6,503,27\mathrm{.}2\%,1,763],[$Total equity funds,$$12,728,53\mathrm{.}3\%,4,456],[$Bond funds$],[$Investment grade,$$2,518,10\mathrm{.}5\%,579],[$High yield,$355,1\mathrm{.}5\%,250],[$World$,541,2\mathrm{.}3\%,329],[$Government$,394,1\mathrm{.}6\%,188],[$Multisector$,530,2\mathrm{.}2\%,221],[$Single$-$state municipal,$191,0\mathrm{.}8\%,279],[$National municipal,$686,2\mathrm{.}9\%,271],[$Total bond funds,$$5,214,21\mathrm{.}8\%,2,117],[$Hybrid $($bond$/$stock$)$ funds,$$1,620,6\mathrm{.}8\%,723],[$Money market funds$],[$Taxable$,$$$4,228,17\mathrm{.}7\%,265],[$Tax$-$exempt,$105,0\mathrm{.}4\%,75],[$Total money market funds,$$4,333,18\mathrm{.}1\%,340],[$Total$,$$$23,896,100\mathrm{.}0\%,7,636]]$

Note: Column sums subject to rounding error.

Source: $2021$ Investment Company Fact Book, Investment Company Institute.