So far this year, Team 900 Students/Mentors have logged 3949 hours. Since build season started we've had 2040 hours logged. Those numbers only count logged hours. At least one mentor never remembers to sign in, and if a student forgets to sign out they get credited for only 1 minute of time.
I also built us a time logging system for our team (and some pretty graphs). Constantly modifying/updating it. If anyone is interested it's open source and can be found here:
https://github.com/FRC900/timesheet