A quarter of those jailed for drunken driving in 1983 had consumed at least 20 beers or 13 mixed drinks when they were pulled over, a Justice Department study said yesterday.

Half of those surveyed had drunk up to two six-packs or eight mixed drinks, according to the report by the department's Bureau of Justice Statistics. The largest category of those arrested were 21-year-olds. Most of those arrested had been drinking for at least four hours and the men drank twice as much as the women, the study said.

The survey of prisoners convicted of drunken driving also showed that between 1970 and 1986 the number of arrests for driving under the influence of alcohol or drugs jumped by 223 percent.

In 1986, an estimated 1.8 million people 16 years and older were arrested for drunken driving; in 1983 -- the peak year -- there were an estimated 1.9 million arrests, or one for every 80 drivers, the report said.

It found that most people, 54 percent, reported drinking beer before their arrest, while 2 percent drank wine, 23 percent liquor, and 21 percent said they had been drinking two or more kinds of alcoholic beverages. The last group consumed the most alcohol, the study said, about three times more than those who had drunk only beer.

Convicted offenders were estimated to have consumed a median of 6 ounces of alcohol, the equivalent to the alcohol content of 12 bottles of beer or eight mixed drinks, the report said.

About 9 percent of the convicted offenders had consumed less than 2 ounces of alcohol; 38 percent consumed between 2 and 5 ounces; 27 percent between 5 and 10 ounces, and 26 percent reported drinking the equivalent of 10 or more ounces.

To consume 10 ounces of alcohol would require drinking 20 beers or 13 mixed drinks, it said.

The report also noted that almost half of the people in jail held on drunken driving charges or serving a sentence for that offense had been sentenced for the same offense at least once before.

The arrest rate in 1983 was highest for 21-year-olds -- one arrest for every 39 drivers that age. The study said that since 1983, most states have adopted laws raising the minimum age for alcoholic beverage consumption to 21 years old, and the arrest rate for people from 18 to 20 has fallen by 14 percent since then.