The average Greek drug addict starts taking narcotics at the age of 15-and-a-half, becomes hooked on a particular substance three years later and first makes contact with a rehabilitation center after another three or four years, according to research made public yesterday. A study by the Therapy Center for Dependent Individuals (KETHEA) of drug addicts who approached the center’s clinics all over Greece between 1995 and 2002 found that the overwhelming majority (82 percent) took heroin. The second most popular drug was cannabis (12.2 percent in 2002, up from 7.3 percent in 1995). The KETHEA study found that although use of heroin increased steadily between 1995 and 2002, addicts are turning to safer ways of taking the drug. Intravenous use fell to 46.8 percent in 2002, from 73.2 percent in 1995, while the percentage of addicts smoking or sniffing the drug reached 14.8 and 19.1 percent, respectively, in 2002 (up from 2.4 and 2.8 percent, respectively, in 1995).