You can really manipulate your push-up count with small variations in technique so rep numbers don't mean a lot to me. 20 good push-ups can be harder than 50 cheap ones.
When people say they are doing 70-100 in a row, they are either in really, really good shape, have short arms, or most likely they are not going down all the way. Your body has to be like a board, flat, and it all has come down to the ground, from nose to your chest to your crotch to your knees all touching the ground at the same time. No butts sticking up in the air and half-distances, which is what I see in 99% of the people trying to do reps to impress. Some people don't go that far down to go easy on their shoulders, but don't brag that you can do 100 then. Otherwise it's just too hard to compare what a full push-up is.
Sorry for the rant, I have just heard way too many guys bragging about their push-up count only to see them skimping their reps.
As for me, I don't do a lot of push-ups. When I am in shape I can do about 40 good, full push-ups as I described, but I am thin and have very long arms. My bench press is also low.