Question:
How many major countries use fiat currency? Are there any non-fiat countries left?
Answer:
There are technically no non-fiat currencies left. However, the U.S. dollar enjoys quasi-fiat status because it is the worldwide reserve currency due to petroleum transactions being denominated in dollars. We are also the hired thugs for the oil monarchies in exchange for dollar denominated international oil sales. We can buy billions of China's exports in dollars (not having to sell them something in Yuan before or after) because they can then turn around and buy oil (or U.S. treasury bonds) with our dollars. Therefore, oil backs the dollar. That's why oil prices rise when the dollar falls and it's why we invaded Iraq when Saddam started selling his oil in Euros (one of Paul Bremer's first decrees as Governor of Iraq in the Coalition Provisional Authority was to declare all Iraqi oil transactions henceforth to be denominated in dollars).
Rather than Saddam's Euro oil sales wrecking our financial system as they feared, Wall Street Ponzi-financial engineering and the President's irresponsible foreign and domestic policies did it all on their own. It's astonishing.