Full disclosure - or not, as the case may be: WWE performer salaries are not made public, and those sources that claim to know about such matters usually possess the journalistic integrity of Piers Morgan, hawking newspapers with Fake Piss News.
"Forbe" it from me to doubt the credentials of certain institutions, but it's all something of a guessing game. The integrity of the mathematics is about as suspect as WWE's attendance numbers. Since WWE lies about those numbers for "entertainment purposes" - including fans, venue staff and talent alike - who's to say WWE wouldn't embellish salary information, even if it were made public?
Instead, we'll have to - in the absence of any real data - carry this out as an exercise of inference and deduction. It doesn't take Sherlock Holmes to determine that Brock Lesnar is on an absolute b*stard fortune, and your average homegrown NXT undercard recruit, like a Tye Dillinger, hasn't had much in the way of a tenure-driven increase.
We might cite the odd source, but we're by no means taking their exact word for it...