A total of 11.1% of Americans 16 or older admitted to driving under the influence of alcohol during the previous year, according to newly released research based on a 2014 federal survey.

This rate of drunken driving in the U.S. is the lowest since the annual survey began in 2002, but the statistic has a noteworthy asterisk. The data, compiled as part of the National Survey on Drug Use and Health, relies on self-reporting during interviews. Drivers are notoriously unreliable when it comes to assessing their own level of impairment, and there’s no guarantee all survey participants answered truthfully.

Nonetheless, the same research methodology has been employed since 2002, so the latest survey results may shed light on overall trends. In 2002, for example, 15.3% of Americans admitted to driving drunk in the previous year.

The 2014 survey results also indicate that 4.1% said they drove under the influence of illicit drugs during the previous 12 months, and 2.8% admitted to driving under the influence of both alcohol and illicit drugs. A total of 2.4% said they drove under the simultaneous influence of alcohol and illicit drugs.

“The percentage of people driving under the influence generally increased with age through the young adult years and then declined with age thereafter; percentages were higher among males than females,” a survey summary published by the Substance Abuse and Mental Health Services Administration (SAMHSA) reported.

The percentage of people who said they drove impaired by alcohol in 2014 (11.1%) was lower than the percentages in 2002 through 2012 (ranging from 11.8% to 15.3%).

"Although it is heartening to see a downward trend in levels of driving under the influence of alcohol, it still kills thousands of people each year and shatters the lives of friends and loved ones left behind,” said Frances Harding, director of SAMHSA’s Center for Substance Abuse Prevention. “We must strive to save lives by reducing this public health threat through education, prevention, and all other possible measures.”

To view the survey results, click here.