A new thread at DigitalPoint Forums polls members on the number of hours they spend with AdSense. That includes your advertising time, your content writing, your coding and your account management. The time slots are broken down pretty broadly, and should most likely be broken down more narrowly. Of currently 48 members polled, here is the break down.
1 - 2 Hrs daily 16 37.21% 3 - 5 Hrs daily 12 27.91% 6 - 8 Hrs daily 6 13.95% 10 - 12 Hrs daily 5 11.63% 13 + Hours daily 4 9.30%
Forum discussion at DigitalPoint Forums.