"During 1999–2008, overdose death rates, sales, and substance abuse treatment admissions related to OPR increased in parallel (Figure 2). The overdose death rate in 2008 was nearly four times the rate in 1999. Sales of OPR in 2010 were four times those in 1999."
Centers for Disease Control and Prevention, "Vital Signs: Overdoses of Prescription Opioid Pain Relievers — United States, 1999–2008," Morbidity and Mortality Weekly Report (Atlanta, GA: 2011), Vol. 60, No. 43, p. 1488.