The most commonly counterfeited denomination is $20. There is around $824 billion dollars in currency circulating throughout the system at any given time. That is a lot of bread.
So how much of it is counterfeit? According to some sources, more than $60 million in counterfeit currency is also floating throughout the system.
In fiscal 2009, the U.S. Secret Service removed more than $182 million in counterfeit currency from circulation. That's more than double the amount in fiscal 2008.
If you get a phony bill, you'll probably be stuck. The government will not replace it, and merchants and banks will probably confiscate it. And since passing counterfeit bills is illegal, you might have to answer to police.
Cash-based businesses such as gas stations, liquor stores, fast-food restaurants, convenience stores and mom-and-pop grocery stores are the obvious targets.
Real bills have a thin vertical strip of fluorescent polyester thread woven in that, under UV light, glows a different color and spells out the currency's denomination for each bill.