According to a new report from Zendrive, a provider of smartphone-based road safety assistance software, cell phone use while driving may be even more common than we think. According to data collected during 570 million trips by 3.1 million drivers in the United States, drivers use their phones in 9 out of 10 trips. While this is an astonishing number, what’s even more worrisome is the finding that drivers spend an average of 3.5 minutes using their phones during an hour-long trip.

As our chart illustrates, cell phone usage behind the wheel causes tens of thousands of accidents every year, needlessly killing hundreds of people. The number of phone-related crashes has increased by 50 percent since 2010, and it is probably no coincidence that the number of people killed in motor vehicle crashes surpassed 40,000 for the first time in years in 2016. As Zendrive notes, the official figures published by the National Highway Traffic Safety Administration probably understate the role of cell phones in traffic accidents significantly, as it is hard to figure out whether a phone was used and drivers are unlikely to admit to it when questioned.