"The joint UNODC/WHO/UNAIDS/World Bank estimate for the number of people who inject drugs (PWID) for 2014 is 11.7 million (range: from 8.4 to 19.0 million), or 0.25 per cent (range: 0.18-0.40 per cent) of the population aged 15-64. PWID experience some of the most severe health-related harms associated with unsafe drug use, overall poor health outcomes, including a high risk for non-fatal and fatal overdoses, and a greater chance of premature death.97 This is exacerbated by poor access to evidence-informed services for the prevention and treatment of infections, particularly HIV, hepatitis C and tuberculosis.98

"Eastern and South-Eastern Europe is the subregion with by far the highest prevalence of injecting drug use: 1.27 per cent of the population aged 15-64. The subregion accounts for almost one in four (24 per cent) of the total number of PWID worldwide; almost all PWID in the subregion reside in the Russian Federation and Ukraine. In Central Asia and Transcaucasia and in North America, the prevalence of injecting drug use is also high: 0.72 per cent of the population aged 15-64 in Central Asia and Transcaucasia; and 0.65 per cent in North America. Those three subregions combined account for 46 per cent of the total number of PWID worldwide. Although the prevalence of injecting drug use in East and South-East Asia is at a level below the global average, a large number of PWID (27 per cent of the total number of PWID in the world) reside in the subregion, given that it is the most populated subregion. Three countries (China, Russian Federation and United States) together account for nearly half of the total number of PWID worldwide."

Source

United Nations Office on Drugs and Crime, World Drug Report 2016 (United Nations publication, Sales No. E.16.XI.7), p. 14.
https://www.unodc.org/wdr2016/
https://www.unodc.org/wdr2016…
https://www.unodc.org/doc/wdr…