Positive drug tests in the workplace are up for the first time in a decade, indicating that the legalization of recreational marijuana in Colorado and Washington could be potentially having an impact on employment.

Madison-based Quest Diagnostics confirmed that out of the 7.6 million drug tests they gave nationwide in 2013, 3.7% of them came back positive. That's a slight increase from the 3.5% of positive tests in 2012, but the numbers remain historically low compared to the peak of 13.6% in 1988. Ironically, once Nancy Reagan and her "Just Say No" campaign left office, the numbers drastically dropped during the late '90s and 2000's, eventually hitting its low of 3.5% between 2010 and 2012.

Marijuana was the most common drug to turn up in Quest tests, with 44% of all positive tests coming back positive for pot. Amphetamines came in second at 20.4%, followed by opiates at 9.8%, benzodiazepines at 9.3%, and cocaine at 4.6%.

However, the types of drugs coming up in positive tests shouldn't be entirely shocking since a new government report found that marijuana is the most commonly used drug in the U.S. Using data from the 2013 National Survey on Drug Abuse, the report showed that more than 20 million Americans over the age of 12 used marijuana in the last year. Non-medical prescription drug use came in second with 4.5 million users in the last year, followed by cocaine at 1.5 million.