For every 8 hours at work, how much time do you spend doing nothing useful?

[osed125]

As a programmer who needs to meet deadlines I don't really have a lot of time to waste. Without counting breaks I say that maybe 30 minutes or so. Most of those 30 minutes are here on VGChartz

Edit: The thing is that in between projects I usually have a lot of time to waste. I have spent 2 weeks without anything to do while I wait for my boss to assign me a new project. They are somewhat of a mini vacations I guess.