I used to get 80-100% grades in elemantary school all the time but over the years, the grades of mine were decreased. In eighth grade I started to have 60-70% grades from time tio time. In high school when I got tired of studing, I started to get so low grades (10-60%) occasionally, heck even I had 0 for not even giving a crap about an exam oncd, as well as not knowing so much about it, my paper was all blank lol. I still managed to past and I got 70-100 grades from time to time (often in English). Later in second half of 11th grade, my grades were increased and they got better and better in last year of high school to the point I got "appericiation certificate". Still no 1st-7th grade quality but I did quite well in my last year.
I had mediocre grades at my college exams (every student around Turkey who finished high school) but I managed to get a decent college.
Our grades in prep-class in college were weirr but I always got high scores because prep-class was all about English. Now that I passed prep-class, I hope I do so well in first class.