My course started with 28....26 passed aerodrome.The 2 that failed? 1 is an assistant. the other a tower controller(non nats). 6 went on to do tower(nats) 5 are valid/1 now an assistant. Of the 20 remaining that did area we lost 6(3 now tower atco's, 1 assistant, 2 resigned)
14 went on to unit training. 8 are now valid, 1 now a tower atco and 5 still training. Each course is different some have higher/lower pass rates and medical/compassionate recourses as well. But if you go through the numbers, in general the majority are still working for the company albeit different roles. The key is if you work hard you will get through. If you don't you can look back and say you gave it your best shot.