"The positivity rate in urine testing for cocaine increased for the fourth consecutive year in the general U.S. workforce and for the second consecutive year in the federally-mandated, safety-sensitive workforce. Cocaine positivity increased 12 percent in 2016, reaching a seven-year high of 0.28 percent, compared to 0.25 percent in 2015 in the general U.S. workforce, and seven percent among federally-mandated, safety-sensitive workers to 0.28 percent, compared to 0.26 percent in 2015."

"A drug’s metabolite is the compound produced when the body processes a particular drug. Identifying these compounds is the focus of workplace drug testing analysis. Marijuana possesses the greatest total number of detectable metabolites at 31 but fewer major components. For amphetamines, no metabolites are identified because these substances normally pass through the body essentially unchanged in chemical structure."

"Marijuana positivity continued its upward climb in both the federally-mandated, safety-sensitive and general U.S. workforces. In oral fluid testing, which detects recent drug use, marijuana positivity increased nearly 75 percent, from 5.1 percent in 2013 to 8.9 percent in 2016 in the general U.S. workforce. Marijuana positivity also increased in both urine testing (2.4% in 2015 versus 2.5% in 2016) and hair testing (7.0% in 2015 versus 7.3% in 2016) in the same population.

According to Quest Analytics, the drug positivity rates for US employees subjected to urine drug tests are:
Federally Mandated Safety-Sensitive Workforce: 2.0%
General US Workforce: 4.9%
Combined US Workforce: 4.2%

Click here for the complete datatable of Drug Positivity Rates Of US Employees Subjected to Urine Drug Tests, by Worker Category