Prevalence of Needle Sharing Among Young Adults Aged 21-30 in the US
" The proportion of 21- to 30-year-olds who say they have ever shared needles in this way during their lifetime is 0.5% overall—0.5% of males and 0.4% of females (Table 1a). As noted in the next section, 1.6% of the full samples say they have ever injected a drug, so this indicates that a minority — but still nearly a third — of the people injecting any of the several drug classes mentioned in the question (heroin, cocaine, amphetamines, or steroids) shared a needle at some time.
" The proportion of 21- to 30-year-olds who say that they have shared needles in the prior 12 months is 0.1%, with 0.2% of males and 0.1% of females reporting such behavior (a non-significant gender difference). This compares to 0.5% who said that they have injected a drug in the prior 12 months, so about one fifth of past year injectors shared a needle during that interval."
Johnston, L. D., O’Malley, P. M., Bachman, J. G., Schulenberg, J. E., Patrick, M. E.. & Miech, R. A. (2013). HIV/AIDS: Risk & Protective Behaviors among American Young Adults, 2004–2012. Ann Arbor: Institute for Social Research, The University of Michigan, p. 18.