The number of people aged 16 and over who drove while under the influence of alcohol in 2014, according to recent report from the Substance Abuse and Mental Health Services Administration -- Driving Under the Influence of Alcohol and Illicit Drugs. This represents 11.1% of the driving population. Additionally:
10.1 million (4.1 percent) drove under the influence of illicit drugs in the past year. About 7.0 million (2.8 percent) drove under the influence of alcohol and illicit drugs in the past year, including 5.9 million (2.4 percent) who drove under the simultaneous influence of alcohol and illicit drugs in the past year.
According to the report, the percentage of people driving while impaired "increased with age through the young adult years and then declined with age thereafter, and was higher among males than females.