A line chart with four lines tracking the rate of four types of opioid overdose deaths from 1991 to 2021. In the early 2010s heroin and prescribed opioid deaths were the most prevalent. Beginning in 2015, fentanyl without stimulants was the leading overdose death. By 2018 both fentanyl with stimulants and fentanyl without were leading, and continued increasing significantly up through to 2021. As of 2021 more than 10 people per 100,000 in the U.S. were dying of both tracked types of fentanyl deaths. The highest death rate the non-fentanyl deaths ever reached was nearly 4 per 100,000.