Here are some baseline numbers:
http://www.washingtonpost.com/wp-srv/style/guideposts/fitness/post/score.htm

Excellent numbers for men (for full pushups):
20-29 years old: 47 pushups
30-39 years old: 39 pushups
40-49 years old: 30 pushups

Excellent numbers for women (for modified pushups):
20-29 years old: 36 pushups
30-39 years old: 31 pushups
40-49 years old: 24 pushups

How many pushups can you do in a row?

ps I'll do this tonight and report back!