CHICAGO (AP) _ Americans got behind the wheel after drinking too much an average of 14,000 times an hour in 1993, according to researchers who say they may still be underestimating the extent of drunken driving.

And nearly one of every 12 instances involved a driver under age 21 _ too young to drink legally in any state, the researchers reported in Wednesday's issue of The Journal of the American Medical Association.

The findings come from a telephone survey of 102,000 adults age 18 and older, 2.5 percent of whom admitted they had driven ``after having had perhaps too much to drink'' on one or more occasions within the previous month. The researchers believe the study is the first estimate of the extent of drunken driving.

The number of occasions reported each month was multiplied by 12 to get an estimate of approximately 123 million for the year. That number was divided by 8,760 for the estimate of hourly instances.

The prevalence of alcohol-impaired driving was 82 times higher than the 1993 arrest rate for driving under the influence, according to FBI arrest data.

And it probably underestimates the true extent of alcohol-impaired driving, researchers said. Though respondents remained anonymous, the social stigma associated with driving drunk probably prompted them to underreport the number of episodes, researchers said.

Also, since the survey required subjective judgments about their own impairment, many respondents _ especially heavy drinkers _ may have denied that alcohol hurt their driving, researchers said.

And the study excluded teens under 18, among whom alcohol-impaired driving has been shown to be ``quite prevalent,'' the researchers said.

Still, 123 million episodes is a ``huge'' number, said Dr. Robert D. Brewer, a co-author of the report and a medical epidemiologist at the Centers for Disease Control and Prevention.

``There's always a danger that people are going to just sort of throw up their hands and think, `Well, what can we do about this? We've been working on this for a long time. Haven't we done anything?''' Brewer said. ``In fact ... we really have made some progress.''

Alcohol-related crash deaths have declined more than 30 percent since 1982, he added by telephone Monday. However, they still totaled some 17,000 in 1995.

The results are no surprise, although they perhaps understated the problem slightly, said Liz Neblett, spokeswoman for the National Highway Traffic Safety Administration.

``We're pleased that they were able to do something to draw attention to the problem of driving while impaired,'' she said.

Brewer and his team, led by Dr. Simin Liu, formerly of the CDC and now with Harvard School of Public Health, suggest more progress would result from stricter laws, better enforcement and increased effort by physicians to identify and treat alcoholics.