You will probably not be surprised to learn that Uber drivers, who are classified as “independent contractors” and definitely not Uber’s employees, don’t make a ton of money. Just how much Uber drivers actually take home at the end of the day paid is up for debate, though: A March study by MIT researchers, which was contested by Uber, found that the median wage for an Uber or Lyft driver is just $3.37 an hour after accounting for fees and expenses. A more recent study by the Economic Policy Institute released on Tuesday, meanwhile, found that on average, Uber drivers make $9.21 an hour, after Uber’s fee and other expenses are taken into account. That’s lower than the minimum wage in several cities where Uber operates, including Seattle, San Francisco, and New York City, as the graph below shows.

“I have long been skeptical that Uber or ‘gig work’ represents the ‘future of work’ ever since it was clearly established that most Uber drivers do not drive as their main source of income, but rather do so to supplement other income sources,” wrote Lawrence Michel, the researcher who conducted the EPI study.

Regardless of how much these drivers actually make, it seems clear that ride-share drivers aren’t making a living wage. Last year, Bloomberg reported that some Uber drivers work 70-plus hour weeks and sleep in their cars to make ends meet. A class-action lawsuit filed by Uber drivers in May 2017 alleged that Uber charges passengers higher prices than it previously did but didn’t pass those profits onto drivers.

Maybe next time you hail a ride, leave a bigger tip. In cash.