I hate to break this to everyone, but this chart is nonsense. Most people will go their whole lives never seeing a true 6.5" girth, women are so fucking stupid. 98% of the population will never see a 10" dick in real life either. Porn numbers are so exaggerated that all our views on size are completely irrational. Even HERE at a meeting place for the well-endowed, there are probably only about 5 guys who have posted pics of dicks 10" or more, and this is where you'd expect to find them. Now, I realise that most of us don't post our pics, but this chart claiming that 6.5" girth is "ideal to women" is stupid because my WRIST has a 6.25 girth and I wouldn't say authoritatively that I've ever fucked a guy with a dick thicker than that, and I'm waaaaaaaaaay on the upper end of the scales for women for number of sexual partners. Add to that the fact that I have been seeking out larger guys for the last two years, which most women would never do.
Now, is the size group listed as "ideal" nice to find? Oh hell yeah, but RARE.