DENVER (KDVR) — Another piece of Colorado’s traffic puzzle is in place.

The state’s roads have gotten deadlier in the last decade as a new influx of residents clashed against COVID-borne driving habits. Law enforcement reported never-before-seen numbers of reckless and aggressive driving, extreme speeding and pedestrian distraction.

It all coalesced into a record year for traffic crash deaths. Officials with the Colorado Department of Transportation said early data shows the number of people who died in traffic crashes last year in Colorado, 745, was the highest the state has seen in more than 40 years.

New data says some of that can be chalked up to impaired drivers. It isn’t the nation’s worst, but Colorado has a higher-than-average level of DUIs. Statewide, 21% of all deadly crashes involved a severely impaired person.

There were 50 DUIs per every 10,000 drivers in the years between 2010 and 2019, according to an analysis of driver and crash data from insurance broker QuoteWizard. This is the nation’s 15th-highest rate, above the national average of 33 per 10,000 drivers.

Rates are generally higher in the western U.S. The Dakotas and Wyoming have the nation’s highest DUI rates, while they are lowest in Delaware and the southeastern U.S.

Despite the higher-than-average DUI rates, impaired driving rates have improved in Colorado. Between 2010 and 2019, the state’s DUI rate dropped by 27%.