A new report from a leading drug-testing firm finds that 4.1 percent of U.S. workers tested positive in 2005, down from 4.5 percent in 2004, the San Antonio Express-News reported June 20.

Quest Diagnostics, Inc., analyzed results from 7.3 million drug tests administered last year. "During 2005, we detected a downward trend in amphetamines and methamphetamines positive test results in the general U.S. work force, and in 2006 the trend took hold among all U.S. workers," said Barry Sample, Quest's director of science and technology. Marijuana was the drug most likely to generate a positive drug test; 52.5 percent of positive drug tests were for marijuana, down from 60.6 percent in 2001. Cocaine was next, accounting for 15.7 percent of positive drug tests.

The drop in positive tests for meth may be due to new state laws limiting availability of over-the-counter pharmaceuticals that can be used to make the drug, Sample said.