Hmm, I'm not sure really. I knit off and on all day, I guess. Sitting in front of the TV, no matter what time it is, or what's on, I'm knitting. And I take my knitting with me everywhere if it's a small enough project (I've really only done small ones so far).
I do have 2 young kids, one 7yo daughter and one 3yo son. They occupy themselves and each other a lot, though.
I guess if you break it down, it's anywhere from 0-5 hours a day.