"Combined 2006 to 2008 data indicate that an annual average of 425,000 persons aged 12 or older (0.17 percent) used a needle to inject heroin, cocaine, methamphetamine, or other stimulants during the past year
"One eighth (13.0 percent) of past year injection drug users had used a needle that they knew or suspected someone else had used before them the last time they used a needle to inject drugs
"Less than one third (29.0 percent) of past year injection drug users cleaned the needle with bleach prior to their last injection
"More than one half (52.8 percent) of past year injection drug users purchased the last needle they used from a pharmacy, and 12.4 percent obtained the needle through a needle exchange program"

Source

Substance Abuse and Mental Health Services Administration, Office of Applied Studies. (October 29, 2009). The NSDUH Report: Injection Drug Use and Related Risk Behaviors. Rockville, MD, p. 1.
http://media.samhsa.gov/data/…