More than 460,000 people attended the 10-day rally.

Nineteen percent of the 1.4 million new coronavirus cases in the U.S. between Aug. 2 and Sept. 2 can be traced back to the Sturgis Motorcycle Rally held in South Dakota, according to researchers from San Diego State University’s Center for Health Economics & Policy Studies. That’s more than 266,000 coronavirus cases attributed to the 10-day event, which more than 460,000 people attended despite fears it could become a super-spreader event.

Officials say next year’s rally will be scheduled for only 9 days due to the lack of boleys.