About 6 hours a day, six or seven days a week. Most of the time is wasted on GameDev, so probably only about 1 1/2 hours a day is actual work, on average.
When I'm making good progress, alot more of the hours go to actual programming work.
When I'm not making progress, alot more of the hours go to browsing GameDev and helping newer programmers. You can chart the progress of my game by watching how fast my GameDev rating rises - huge increases in rating indicates slow progress of my project.