SAN DIEGO -- About 61 percent of San Diego County arrestees tested positive for at least one illegal drug when they were booked last year, it was reported Saturday.

Figures from the San Diego Association of Governments, based on data was gathered from 764 men and women who participated in the study, showed that men tested at the lowest rate in seven years -- 57 percent, down from 66 percent in 2006, The San Diego Union-Tribune reported.

The number of women drug users also declined, for the first time, over the same period. Just 69 percent of the women booked showed signs of illegal drug use compared to 75 percent in 2006.

Of the participants, 82 percent had been arrested before; 32 percent had been in a gang or associated with one; 30 percent knew at least one parent used drugs; 66 percent committed property crimes in the past year; and 23 percent had been diagnosed with a mental illness, according to the Union-Tribune.

Half of methamphetamine users reported that the drug was becoming harder to find.

The study found that cocaine was becoming harder to buy, too. Marijuana remains the most used drug in the county and nation, as well as the easiest to obtain, the study found.