"The prevalences found by way of this study show that 0.4% of the age 15-64 population has injected heroin, cocaine or other illicit drugs sometime in their lives (0.6% of the males and 0.2% of the females). Focusing on the results by the ages of those interviewed, those individuals who are within the 35-44 age group are found to be those showing the highest prevalence (0.8%) (Table 2.37)."

Source

Government Delegation of National Plan on Drugs (Reitox National Focal Point for Spain), "2012 National Report (2011 Data) to the EMCDDA: Spain: New Development, Trends and in-depth information on selected issues" (Madrid, Spain: DGPNSD, Dec. 2012), p. 85.
http://www.emcdda.europa.eu/h…
http://www.emcdda.europa.eu/a…