Drug use in the workforce has dropped to the lowest level in 18-years.
Last year, quest diagnostics tested more than nine-million people for drugs and only 3-point-8 percent tested positive.
That is down from a high of 13-point-six percent in 1988.
Officials do not know if the decline is influenced by devices that allow people to fool test administrators.
Quest diagnostics is the Nation's largest provider of employee drug testing.