Hmmm.
4 hours a day is a lot of time on just "non-essential" activity. I switch around a lot, so I don't have an exact count, but there are days when I'm sure I qualify.
A lot depends on what kind of "unessential activity" someone is doing. I do roughly the same thing on a computer as I would do browsing at a very good library full of current periodicals and older, more interesting stuff. That's something I could easily kill 4 hours a day on, and before the internet, sometimes did. I love information.
How about people who spend 4 hours a day watching TV? I hardly watch TV at all.