After public education, what is usually the second greatest expense for state governments?

In FY 2017, total US government spending, federal, state, and local, is "guesstimated " to be $7.04 trillion. Federal spending is budgeted at $4.15 trillion; state spending is "guesstimated" at $1.72 trillion; local spending is "guesstimated" at $1.87 trillion.