Well this one is Comicpalooza, so it is more comic oriented than anime, though anime cosplayers will absolutely be there as well. Obviously going to vary a bit, but at most cons somewhere between 20 and 40 percent of people cosplay. The majority of people will not be in costume.
The Chattanooga one must be the exception. About 80% of the people who weren't running events or selling stuff were in costume. 20% of those people were cute girls who shed their introvert shells to dress up as slutty foxes or bakeneko or something to that extent. Another 20% were from homestruck and were meh. Maybe 5% were furry. There was a whole family that dressed up as characters from One Piece. The toddler Luffy was adorable.
Also, did I ever tell the story of my magic penis? No? Maybe? Whatever. At the last convention, as a buddy and I were sitting in front of the registration for the cosplay contest, a person in a wolf fur suit (I don't know the proper term. She was a wolf and there was probably a zipper for her naughty bits) walked by. I said to my friend, "What do you think she's from?" My friend said, "Dunno. And how do you know she's a she?"
So it turned into a game between us of guessing the gender of furries. And of the ones who took of their suits in front of us, I was seven for seven.
That's right. I can tell the gender of genderless wolf people.
I don't know how many people will be dressed up, I've never been to one. Sounds like a fun idea though.
I never dress up and feel like the odd man out every time. Some of those costumes are amazingballs and the free time required to look cool (sic) must be enormous. I'm not enough of a nerd to cosplay.