Counterfeit money is tracked and reported by parts per million (PPM), which reports how many counterfeit banknotes have been passed into circulation out of 1 million. G-20 countries use a benchmark of 50 as an acceptable level of counterfeiting.
In 1990 Canada has a PPM of 4, which means out of 1 million genuine currency bills, 4 counterfeit bills were being passed into circulation.
In 1997, the rate in Canada increased to 117. By 2004, the rate was 470 PPM.
In 2002, up to 10 percent of retailers across the country were no longer accepting the Canadian $100 bill in order to protect themselves from counterfeits.
After enacting changes to its currency, Canadian officials reported that 2008 the PPM of counterfeit money was 76, and down under 40 PPM in 2011.
Source: Grant Robertson, “Funny money: How counterfeiting led to a major overhaul of Canada’s money,” Globe and Mail, December 3, 2011.