If you live in the United States or Canada, chances are you have cocaine in your wallet.

Nearly nine out of ten bills circulating in the U.S. and its northern neighbor are tainted with cocaine, according to what's being called the most definitive research to date on the subject.

What's more, researchers were surprised to find hints that more Americans are using the illegal drug, said study leader Yuegang Zuo of the University of Massachusetts in Dartmouth.

In a similar study by the same team in 2007, 67 percent of U.S. bills were found to be tainted with cocaine. The new study puts the percentage at 85 to 95—a jump of roughly 20 percent, Zuo said.

The drug gets on paper money