I work at the computer selling company, so 14-16 hours definitely stare at the monitor, including 4-6 at home.
Uhmm let me count. I wake up at 6 am, usually stay on until 9, take a shower, then I'm on the computer until 7pm, I stop to have dinner, I also walk my dog about 30 minutes each day.. after that I use the computer until 12.. that's about 12-15 hours each day.