I can't imagine (outside of Texas) its very high at all. Most elementary schools dont have anything besides a basic field and gym and the cost per them is usually slightly higher than high school.

The biggest increases in expenditures are specialists for children with speech problems, reading problems, learning disabilities etc. as professions like speech language pathologists usually earn considerably more than teachers and the number of them within any school has increased considerable too. I'm not making a value judgement - that's just where the money is going.