Missouri Region VII had 20 teams in C division this year, up from 17 last year. B is usually larger for us, with 22 B teams this year. It really just depends on what area you're in, and when you're competing. Some schools might not compete every year.
(Projected) 2019-2020 Events (C): Astronomy, Designer Genes, Forensics, Write It Do It
2018-19 Events (C): Designer Genes, Fossils, Write It Do It (formerly also Mousetrap Vehicle and Experimental Design)
2017-18 Events (B): Rocks and Minerals, Wright Stuff, Write It Do It
I edit the wiki sometimes.