I teach at one huge high school. There's only 900 students, but the school is massive. It's a technical school, so half of the school consists of computer labs, dance halls, etc.. It has the capacity to hold over 2,000 students. I teach all 30 classes, the 2nd and 3rd years alternate weeks. They range from 22-28 students. I had a few classes with only 5-6 students because the rest went off to work. They can get jobs and work before graduating at technical schools. They still graduate on time, but they don't need to attend.