"The number of drug overdose deaths per year increased 54%, from 41,340 deaths in 2011 to 63,632 deaths in 2016 (Table A). From the literal text analysis, the percentage of drug overdose deaths mentioning at least one specific drug or substance increased from 73% of the deaths in 2011 to 85% of the deaths in 2016. The percentage of drug overdose deaths that mentioned only a drug class but not a specific drug or substance declined from 5.1% of deaths in 2011 to 2.5% in 2016. Review of the literal text for these deaths indicated that the deaths that mentioned only a drug class frequently involved either an opioid or an opiate (ranging from 54% in 2015 to 60% in 2016). The percentage of deaths that did not mention a specific drug or substance or a drug class declined from 22% of drug overdose deaths in 2011 to 13% in 2016."
Hedegaard H, Bastian BA, Trinidad JP, Spencer M, Warner M. Drugs most frequently involved in drug overdose deaths: United States, 2011–2016. National Vital Statistics Reports; vol 67 no 9. Hyattsville, MD: National Center for Health Statistics. 2018.