How many reps?
For a 1-rep max, I'd say "av'g Joe" (normal 160-180lb guy, no injuries, good health) would probably be around 165-185....essentially BP their own body weight.
FWIW, I've trained with a few "little" guys (and girls) who could put up some suprising #'s considering their size (or lack thereof lol)
1) a 24 y.o. kid who's 6'3", and maybe 160 lbs soaking wet...was putting up 135 for 4-5 reps...not too bad.
2) 28 y.o girl who's 5'7" and weighs around 105 did 95 lbs for reps....again, I was impressed. (she squatted 135 for reps until I made her quit!!! lol)
On the other hand, back in HS (1982-ish) I trained with a friend who was 1 of the stars of our HS gymnastics team...5'6", 170-ish lb tank...he was putting up 355+ for reps with ease (yes, he had...ahem..."help"...if you know what I mean)