i think overall its aobut 60% A-B in each subject. don't have stats for average grades per person though. btw i go to a large 6th form college (1200-1400 ppl)
All Ds i would say at mine, despite the fact it gets the some of the smartest people in the borough who will get all As. But then there's a lot, and i mean a lot, who are only on 2 subjects in my year and are on Ds in them.
Last year the average amount of UCAS points from A2 (excluding GS and subjects dropped at AS) was 276.89, so that's about BBC. It's a state school, non-grammar, by the way.
ABB (Grammar school, with non-selective VI Form, i.e. 90 of us were selected in year 7, then 160 more were let in at the start of year 12 (regardless of successes)).
My school is bizarre. 20% get AAA, and a good proportion get at least one A. But then a good proportion also get straight Es and Us, so apparently the school's average is something like CCC. Major divide between the two groups pulls the average down big time, I guess. Dunno what that really says about the quality of the sixth form.