Over the past 15 years, the number of deaths due to cocaine-related causes has seen a pattern of increases and decreases. From 2000 to 2006, the death rate for this drug doubled, then dropped by about 50% from 2006 to 2010, and finally, from 2010 to 2015, it increased again to nearly what it was in the initial six-year measure (all of this data was taken from the National Vital Statistics System). Indeed, the number of deaths caused by cocaine overdoses in the United States was at its highest in 2006, but 2015 was a close second after a period of decline. Many researchers believe there is a connection between cocaine and opioid use, some going so far as to say opioids are one of the factors driving the recent increase in cocaine-related deaths. This could have some validity due to the increase in synthetic opioid production in America. However, the exact cause of the cyclical nature of cocaine-related deaths is still unconfirmed.