Yeah, I just now realized that choices are not very cleverly made. I just expected(haha) that everyone sleeps pretty much as me (maybe I was trying to justify my sleep hours..?).
But now, probably, I should not change choices as there are plenty of votes. Sorry for that.
Try something like: (< 4, 4-5, 5-6, 6-7, 7-8, 8-9, 9+)