The nation lost 35,092 people in traffic crashes in 2015 — a sharp increase compared to the previous year, according to federal data.

The final data released on Monday by the National Highway Traffic Safety Administration (NHTSA) showed traffic deaths rising across nearly every segment of the population, with a total 7.2% increase in 2015 compared to 2014.

The last single-year increase of this magnitude was in 1966, when fatalities rose 8.1% from the previous year.

“Despite decades of safety improvements, far too many people are killed on our nation’s roads every year,” U.S. Transportation Secretary Anthony Foxx said. “Solving this problem will take teamwork, so we’re issuing a call to action and asking researchers, safety experts, data scientists, and the public to analyze the fatality data and help find ways to prevent these tragedies.”

Ten years ago, the number of traffic deaths was nearly 25% higher, with 42,708 fatalities reported nationwide in 2005. Since then, according to NHTSA, safety programs have helped lower the number of deaths by increasing seat belt use and reducing impaired driving. Vehicle improvements, including air bags and electronic stability control, have reportedly also contributed to reducing traffic fatalities.

In response to the spike in deaths in 2015, the Department of Transportation, NHTSA, and the White House have called on a wide range of stakeholders to help determine the causes of the increase. NHTSA will share its Fatality Analysis Reporting System with safety partners, state and local officials, technologists, data scientists, and policy experts.

According to NHTSA, job growth and low fuel prices were two factors that led to increased driving, including increased leisure driving and driving by young people. More driving can contribute to higher fatality rates. In 2015, vehicle miles traveled increased 3.5% over 2014, the largest increase in nearly 25 years.

Pedestrian and pedalcyclist fatalities increased to a level not seen in 20 years. Motorcyclist deaths increased more than 8%.

NHTSA also noted that human factors continued to contribute to the majority of crashes. Almost half of the passenger vehicle occupants killed were not wearing seat belts. Also, research shows that almost one in three fatalities involved drunk drivers or speeding. Meanwhile, one in 10 fatalities involved distraction.

“The data tell us that people die when they drive drunk, distracted, or drowsy, or if they are speeding or unbuckled,” NHTSA Administrator Mark Rosekind said. “While there have been enormous improvements in many of these areas, we need to find new solutions to end traffic fatalities.”