Uber Technologies Inc. reported record monthly bookings for March as Covid-19 vaccination rates accelerated across the U.S.

The company said Monday that it received more bookings in March than in any single month since it was founded in 2009. Uber’s mobility business, which was decimated during the coronavirus pandemic and includes its core ride-hailing operations, had its best month since March 2020. Meanwhile, its food-delivery unit posted record monthly bookings, with business more than doubling year-over-year.

Rival Lyft Inc. said last month that its weekly rides bookings in March had rebounded to pre-pandemic levels.

But both companies face a daunting challenge: not enough drivers to meet surging demand. The companies don’t employ their drivers, relying instead on gig workers to ferry their passengers. As demand for Uber and Lyft rides plummeted during the pandemic, many gig workers turned to work for grocers and food-delivery providers, among other businesses that surged during the health crisis.

The latest round of stimulus checks has also adversely affected driver supply, according to a person familiar with the matter.