Question and statistics about Evo in general

Hey guys
sorry if these questions have already been posted, but I haven’t found any answer so far.
I’m currently working on a college project about competitive gaming, and I’m currently trying to gather information about EVO, like its history, or a few attendance data.
But I really can’t find anything but a few threads with results (which are not that interesting to me, at least regarding my project) and a kotaku article which doesn’t give much precision. I tried to look on the internet archives what I could find on the wiki, but nothing.

So does anyone has a link to some concrete article or summary of Evo history ? Or do some of you know the milestones of Evo, like, say, when it became a multi game event, when it began being held in Vegas ? Or some attendance amounts ?

Thanks for your help, and sorry if my english contains mistakes.