From a few days ago (but still interesting if you haven’t seen it), reading trends on different kinds of devices.
The graph of when users are reading on the iPad shows the biggest time for reading: personal prime time.
This is generally the most relaxing time of day. After a long day, work is done, dinner is resting in your belly and there is nothing left to do but put your feet up and relax. This time slot is the same one coveted by television. When the majority of people are consuming content it seems perfectly natural that people would use this time to do their reading as well.