I agree with Marydean.

I'm a teacher in a government school in rural NSW. Our school has slightly less than 80 students and there are 4 teachers. Kindy is small, year 1/2 (mid 20's) year 3/4 (mid 20's), and year 5/6 (mid teens) just due to the number of students in different stages of schooling. NSW gov schools are generally 20 or less in kinder, up to 24 in years 1 and 2 and up to 31/32 in other grades.