(Bloomberg) American drug deaths rose by 21 percent last year, according to early federal data—a one-year spike that amounts to a bigger jump than over the previous four years combined, showing an already troubling crisis accelerating.

For every 100,000 residents, almost 20 died in drug overdoses in 2016, compared to 16.3 the year before, according to the data released by the Centers for Disease Control and Prevention.

The rate of deaths increased slightly in every quarter of 2016, indicating an accelerating epidemic. That crisis has been driven by opioid abuse, as potent synthetic drugs such as fentanyl and carfentanil, an elephant tranquilizer, circulate more on the black market.

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