Long before the Bush administration began exhorting states to crack down on drug traffickers, the states were well on their way to a tremendous boom in felony convictions for such crimes, according to a Justice Department report released this week.

State courts nationwide convicted 111,950 people for felony drug trafficking in 1988, according to the Bureau of Justice Statistics study. That represents a 46 percent increase over the 76,400 felony drug trafficking convictions in state courts two years earlier.

The increase was more dramatic in the country's 75 most populous counties, which are responsible for more than half of all reported crime. Felony drug trafficking convictions there leaped 61 percent to 64,160.

This occurred as the total of state court felony convictions was increasing at a much lower rate of about 14.5 percent, to a new total of 667,366, according to the report released Sunday.

About one in three state court felony convictions in 1988 was for drug trafficking or possession. Two years earlier, only one in four concerned drug offenses.

Patrick A. Langan, who wrote the report with fellow bureau statistician John M. Dawson, said he believes the increase is due to an increase in lawbreaking and arrests, not to new laws.

For example, he said, "A growing number of states are passing laws that increase the penalty for trafficking drugs within 100 yards of a school. People who are convicted will have to pay a heavier penalty," Langan said, "but it's not as though that wasn't a felony before those laws were passed."

The study's most reliable data concern the 75 most populous counties, Langan said, as those were studied in depth in both 1986 and 1988. The number of counties checked nationwide increased from 100 in 1986 to 300 two years ago.

For the 75 counties, the total number of felony convictions in state courts rose 27 percent to 310,547, compared with 14.5 percent for the nation as a whole.

On a national basis, the report also found:

State courts sentenced 44 percent of convicted felons to state prison, 25 percent to jail, 30 percent to probation and 1 percent to alternative sentences.

Among those convicted of felonies, 91 percent pleaded guilty, 5 percent were convicted by a jury and 4 percent were found guilty by a judge.

About 57 percent of the felons convicted in 1988 were white, 41 percent black and 2 percent other races. Of the total, 87 percent were male. The average age was 29 years.