According to today's data visualization, modern human-beings sit down more during the day than they sleep. I am one of these people.
I'm not happy about it. It isn't healthy to sit around that long, but I do it everyday. Between classes and studying, I almost never stand up. Also, most people with desk jobs don't have the option to stand while they work. We're all in the same boat.
I do slouch sometimes, and I try to sit up straight whenever I can remember, but this infographic does say that leaning back when I sit will lead to less strain on my back. I would hate to have back pain anytime soon. [Via]