Summary statistics for explanatory variables (years: 2002–2011).

Notes.† The number of injectors for each primary substance use (opioid and cocaine) was calculated from each annual Table TDI-17 part-ii and part-iv, respectively, by multiplying the relevant percentage by the number of clients whose usual route of administration was known;†† The total number of injectors was obtained by adding the numbers of injectors of each substance (opioid, cocaine, stimulants, and cannabis), calculated from the percentages in the tables;†††All per population estimates were obtained by dividing the actual variable values (derived from EUROSTAT or EMCDDA) by population estimates derived from Eurostat.Summary statistics for explanatory variables (years: 2002–2011).