"A medical testing company called Quest Diagnostics analyzed decades worth of drug tests – about 125 million of them – and found that only 3.6-percent came back positive for cocaine and marijuana. That’s down from more 13-percent in 1988. Seems like a good trend. But there were some exceptions beginning with prescription drugs. Positive tests for Vicodin and Oxycontin were up sharply over the past few years. And researchers warn the lower rates of pot and cocaine use could also be due to the fact that more people are beating the tests."