The United States has the highest rate of drug-related deaths among a group of 13 developed nations, according to a study published in the Annals of Internal Medicine.

Researchers from the U.S. National Cancer Institute analyzed data from the World Health Organization. They found drug overdoses accounted for 35 deaths in every 100,000 men and 20 deaths in every 100,000 women in 2015 in the United States, HealthDay reports.

These deaths included accidental drug-related deaths and drug-related suicides among adults ages 20 to 64. The study compared U.S. drug-related death rates to those in Australia, Chile, Denmark, England, Estonia, Finland, Germany, Mexico, the Netherlands, Norway, Spain and Wales.

Drug overdose death rates in the United States have more than doubled during the 21st century, reaching an estimated 63,632 deaths in 2016, the researchers noted.