Guess it varies for schools.
Last year, my school had more than 5 SE01 promotees and close to 5 SEO2 promotees. Plus around 5 each for GEO5. Plus other grades.

Then again, it has been some time we had close to 20 promotees . If previous years are very few, perhaps the next or year after will have more. It’s after all dependent on the officers and not the school.