Why not use evenly sized bins?
Poll: Hacker News User Age
11–14 of 14 posts
Re: Poll: Hacker News User Age
#12Re: Poll: Hacker News User Age
#13I never thought of 37 as over the hill. Sheesh.. I've got a 10-month old baby. I'll just accept it as having a rare perspective for someone of my advanced years.
Re: Poll: Hacker News User Age
#1427-30 and 30-35 are overlapping bins.
Sorry, was meant to be 31-35. Typo. You voted in the right bin =]