Teachers make up 72 percent of on-site staff in Arizona’s independent education sector, but less than half of on-site staff in the public sector. In order to match the independent sector’s emphasis on teachers over non-teaching staff, Arizona public schools would have to hire roughly 25,000 more teachers and dismiss 21,210 non-teaching employees.
I am not at all surprised by this. As I pointed out long ago, one of the miracles of public education is that the school system charges more than $10,000 per student, puts 25 students in the classroom, and still pays teachers (far) less than $100,000 per year. The secret for doing this is to pad the school system (and the teacher's union) with non-teaching staff.
Coulson's full study is here. I would bet that where I live in Maryland at least 40 percent of school system employees are not in the classroom. My guess, however, is that in order to avoid embarrassment, the county avoids breaking down the data that way.