A new survey by the Substance Abuse and Mental Health Services Administration (SAMHSA) indicates that on average 13.2 percent of all persons 16 or older drove under the influence of alcohol and 4.3 percent of this age group drove under the influence of illicit drugs in the past year.

The survey's state-by-state breakdown of drunk and drugged driving levels shows significant differences among the states.

Some of the states with the highest levels of past year drunk driving were Wisconsin (23.7 percent) and North Dakota (22.4 percent).

The highest rates of past year drugged driving were found in Rhode Island (7.8 percent) and Vermont (6.6 percent).

States with the lowest rates of past year drunk driving included Utah (7.4 percent) and Mississippi (8.7 percent).

Iowa and New Jersey had the lowest levels of past year drugged driving (2.9 percent and 3.2 percent respectively).

Levels of self-reported drunk and drugged driving differed dramatically among age groups, with younger drivers having a much higher likelihood of driving under the influence of drugs or alcohol.

Drivers aged 16 to 25 had a 19.5 percent rate of drunk driving while drivers 26 or older had an 11.8 percent rate.

Similarly, people aged 16 to 25 had a much higher rate of driving while under the influence of illicit drugs than those aged 26 or older (11.4 percent versus 2.8 percent).

The one bright spot in the survey is that there has been a reduction in the rate of drunk and drugged driving in the past few years.

Survey data from 2002 through 2005 combined when compared to data gathered from 2006 to 2009 combined indicate that the average yearly rate of drunk driving has dropped from 14.6 percent to 13.2 percent, while the average yearly rate of drugged driving has dropped from 4.8 percent to 4.3 percent.

Twelve states have seen reductions in the levels of drunk driving and seven states have experienced lower levels of drugged driving.

However according to the National Highway Traffic Safety Administration's Fatal Accident Reporting System (FARS) census, in 2009, one in three motor vehicle fatalities (33 percent) with known drug test results tested positive for drugs.

"Thousands of people die each year as a result of drunk and drugged driving, and the lives of thousands of family members and friends left behind are forever scarred,” said SAMHSA Administrator Pamela S. Hyde, J.D.

Hyde said some progress has been made in reducing the levels of drunk and drugged driving through education, enhanced law enforcement and public outreach efforts, however, "the nation must continue to work to prevent this menace and confront these dangerous drivers in an aggressive way.”

"While we have understood for some time the dangers of driving under the influence of alcohol, much less is known or discussed about drivers under the influence of other drugs,” said Gil Kerlikowske, Director of National Drug Control Policy.

"This new data adds to other emerging research revealing that there is an alarmingly high percentage of Americans on our roadways with drugs in their system. At a time when drug use is on the rise, it is crucial that communities act today to address the threat of drugged driving as we work to employ more targeted enforcement and develop better tools to detect the presence of drugs among drivers.”

State Estimates of Drunk and Drugged Driving is based on the combined data from the 2002 to 2005 and 2006 to 2009 National Surveys on Drug Use and Health (NSDUH) and involves responses from more than 423,000 respondents aged 16 or over.

NSDUH is a primary source of information on national and state-level use of tobacco, alcohol, illicit drugs (including non-medical use of prescription drugs) and mental health in the United States.

The survey is part of the agency's strategic initiative on behavioral health data, quality and outcomes.