In our middle school our rate was more toward 70%. Grade inflation to the extreme, with some well meaning "self esteem" rationale thrown in.
My children and their friends were offended by teachers who discouraged competition.
In these schools all the children are above average*... and all the schools are above average*...
*In these schools "above average" is defined as any IQ greater than zero, any grade better than an F-, and attendance means enrolled (presence not required)!