"In 2011, reports were submitted to the NPR [Norwegian Patient Registry] from 159 units in the specialist health service concerning a total of 8,817 patients who started treatment for primarily drug-related problems (2010: 8,750 patients from 158 units). The number of patients broke down as 3,921 in in-patient treatment and 4,896 in outpatient treatment, including OST [Opioid Substitution Treatment]. Around 68 per cent of the total number of patients in treatment were men. The average age of patients in in-patient treatment was 35 years for men and 34 years for women, fairly similar to patients in outpatient treatment (men: 34 years, women: 35 years)."
Norwegian Institute for Alcohol and Drug Research, "The Drug Situation in Norway 2012: annual report to the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA)," (Oslo, Norway: December 2012), p. 30.