How much does a Sherpa get paid?

I'm curious to know, when it comes to the compensation of Sherpas, what kind of financial rewards can they expect for their dangerous and grueling work guiding climbers up Mount Everest and other challenging peaks? Are there set rates or is it dependent on a variety of factors, such as the season, experience level, and perhaps even the success of the climb? I'd love to gain a better understanding of the economics behind this unique and fascinating profession.