Ever been tempted by a Lyft or Uber email promising you cash if you join their platform? If so, you’re not alone.

The number of self-employed, unincorporated sole proprietors in the passenger transportation industry– presumably mostly people driving for Lyft or Uber — has risen 88 percent in Denver from 2012 to 2014. That’s the tenth-highest increase in the 50 metros that the Brookings Institution studied for their report. 

So as of 2014, there were an estimated 4,680 drivers in the Denver metro. That would include guys like Brian Hewlett though, who prefers working outside the confines of Uber or Lyft, though I suspect there are not a significant number of drivers like him.

Fewer than 5,000 people doesn’t sound like that many, but scaled to a per capita level, it’s fairly big, according to an analysis from City Observatory. They found that there are likely more than 150 drivers per 100,000 residents, which is the eighth-highest concentration.

Anyway, in the tradition of Jon Stewart, here’s your final moment of zen: I find it amusing that Denver’s jump was not as big as the 135 percent jump in Austin. Uber and Lyft left Austin this summer after voters supported requiring fingerprint background checks for drivers.