Is There a Difference Between Expenses and Salaries?

The only part of the data of the disagreement over data that I can remember with any confidence is over the salaries of teachers. Both actually show big increases in payments to teachers from like the 1950s to the 1980s and then it does kind of level off from the 1980s onward. At the same time you know so long as they're getting higher payments relative to productivity growth we would expect that to drive increases in cost. We are hiring more teachers and more teachers age as well trying to try to substitute away.