If you go to the official site and click on ships>viper>CAG roster it'll tell you they have 12 vipers on duty, 23 down for repair, 31 active pilots, and 5 trainees as of episode 110(the most recent). I guess the keep a running tally which is pertty durn cool.
http://www.scifi.com/battlestar/episodes/season01/110/
thats frackin cool that they are keeping that up. I'm guessing they will have to have an episode when they get a way to get more ships/parts.