I've noticed that a lot of people were using the outdated VGC usage images, one where the teams were form one regional in Virginia and the other from 2015.

So I went to http://www.pokemon.com/us/play-pokemon/worlds/2016/teams/masters/ and tallied up the Pokemon myself.

Tweny-four teams made it into the Masters Division. Here are the results.

As expected, Primal Groudon dominated, with a 62.5% usage.
Gyarados and Mega Gyarados are separate entities as only one Gyarados was holding its Mega Stone. I didn't treat Rayquaza the same way because it would have been impractical to find out which Rayquaza were Mega Evolved, so I decided that as every Rayquaza knew Dragon Ascent, it would be acceptable to simply list them all as Mega.
Till Böhmer's Mega Rayquaza is listed as holding a Red Orb on the Pokemon website. We know it was definitely holding a Salamencite, but I listed it just because it threw me off when I was gathering the data and someone else might also get confused if they wanted to check for themselves.

I hope this can be useful in some way. Maybe someone can take the data and make it into a prettier infographic.