Illicit drug use by American teenagers dropped sharply last year, with less than one in 10 youths now saying they use cocaine, marijuana or other illegal drugs, according to a federal survey released yesterday.

While illegal drug use across all age groups remained steady, the decline in teen use marked a significant departure from what had been nearly a decade-long rise in use among youngsters and was swiftly heralded by Clinton administration officials.

"In the battle against illicit drugs, we've turned the corner," said Health and Human Services Secretary Donna E. Shalala, who presented the findings at a news conference with National Drug Control Policy Director Barry R. McCaffrey.

Shalala and other officials credited the drop to increased antidrug efforts on the part of parents, schools and the government. "The message is finally getting through," she said.

According to the National Household Survey on Drug Abuse, 9.9 percent of youths ages 12 to 17 reported that they were using illegal drugs in 1998, compared with 11.4 percent in the same age category the year before.

But yesterday's report, which surveyed 25,500 Americans 12 and older, also found no substantial change in overall drug use across age groups. The survey estimated that, last year, 13.6 million Americans, or 6.2 percent of the population 12 or older, were drug users -- defined as those who had used an illicit drug at least once in the 30 days before they were interviewed for the survey. This did not represent a significant decline from the estimated 13.9 million drug users in 1997, administration officials said.

Overall drug use in the country remained level in large part because an increase among young adults ages 18 to 25 offset the drop among youths. The survey estimated that 16.1 percent of young adults were current drug users last year, up from 14.7 percent in 1997 and the highest level recorded in the 1990s.

Officials noted that this increase was consistent with the demographic bulge of drug users who were teenagers in the mid-1990s. "If you don't affect youth attitudes at ages 9 to 17, you put a bubble into the system and we end up with rates of drug abuse downstream that are increased," said McCaffrey. "We've got to affect our children in the middle school years and the high school years."

According to the annual survey, drug use among 12- to 17-year-olds hit a peak of 16.3 percent in 1979, and declined during the 1980s to reach a low point of 5.3 percent in 1992, the year President Clinton was first elected. Since then, the estimated current drug use by 12- to 17-year-old Americans has risen every year except in 1996 and 1998.

This trend led some to discount the latest report's findings. "The truth is that drug use trends fluctuate over time," said Rob Stewart, a senior policy analyst at the Drug Policy Foundation, which has been critical of the administration's anti-drug efforts.

"We can't look at one-year results and fight youth drug use in such narrow increments. Washington budgets in annual increments, but social trends don't move in the same way," Stewart said.

Joseph A. Califano Jr., a Cabinet secretary in the Carter administration who is now president of the National Center on Addiction and Substance Abuse at Columbia University in New York, applauded the drop among teenagers but noted, "There's no question we've got a long way to go to get back to [the] '92 [level], and we ought to get below that . . . . Saying the country has 13 or 14 million current drug users is not something that anybody is going to applaud."

Califano pointed to the "very bad news" that "African Americans and Hispanics are being savaged" by drug use. One of the largest relative increases measured by the survey was in the use of cocaine by Hispanics, which jumped from 0.8 percent in 1997 to 1.3 percent in 1998, the highest level since 1992.

The survey also reported increases in the use of marijuana by both blacks and Hispanics, compared with a slight decline in marijuana use by whites.

In addition to assessing the use of illicit drugs, the survey measured tobacco and alcohol use among Americans. It estimated that 60 million Americans 12 or older -- or 27.7 percent of the population -- smoked cigarettes in 1998. That represented a significant decline from the 1997 rate of 29.6 percent and is the lowest rate of cigarette smoking ever recorded, according to the survey. However, it added that cigar use appears to be on the rise, from a rate of 5.9 percent in 1997 to 6.9 percent in 1998.

The survey estimated that 2.1 million people began smoking cigarettes daily in 1997, the most recent year for which data are available, and that more than half of the new smokers were younger than 18. It said that, in 1998, an estimated 4.1 million youths, or 18.2 percent of the 12- to 17-year-old population, were current cigarette smokers.

Slightly more than half of all Americans 12 and older were current users of alcohol in 1998, including 10.4 million who were ages 12 to 20, the survey said. Of this youngest group, 5.1 million engaged in "binge drinking," defined as having five or more drinks at least once in the 30 days before the survey interviews.

CAPTION: DRUGS IN AMERICA (This graphic was not available)

CAPTION: DRUG USE BY YOUNG (This chart was not available)