Most of those monitored in 1988 were sentenced offenders on probation and parole who were taking part in a program of intensive supervision in the community. A few had been released either pretrial or while their cases were on appeal. Many monitoring programs involve small numbers of offenders. Those monitored in both 1987 and 1988 were mainly men who ranged in age from 10 to 79. A quarter were charged with major traffic offenses, usually driving under the influence or while intoxicated. Property offenders were also strongly represented, while drug law violators made up 15.3 percent of those monitored. Monitoring was done using either continuously signaling devices or programmed contact devices that contact offenders periodically to verify their presence. Monitoring programs have expanded rapidly in the short time they have been used. Figures.