Remember how Valve released some statistics, charts, and "Death Maps" for Episode 2? If you didn't, then you should probably click on the words "Episode 2" in that last sentence.
Valve is at it again with a large list of compiled stats for Team Fortress 2. You can find information on which class is played the most, the average points per hour, and other nifty stats. I really wouldn't figure the Sniper to be the class that generates the most points per hour.
Possibly the most useful of this information (As far as game balance is concerned) comes from the information showing the balance of the maps based on what team wins the most. Dustbowl is apparently the most lopsided map, with Red winning over 70% of the time. Hydro is currently the most balanced with a near 50/50 split.
http://www.steampowered.com/status/tf2/tf2_stats.php
Source:
http://www.csnation.net