Sure, I realize these statistics cannot be calculated exactly, and, sure, I realize there are definitional issues within a country and choices to be made when converting to other currencies. Still, there’s a lot of variation here!
At the very least, this is a good example for a statistics, economics, or political science class to illustrate the difficulties of measurement.
P.S. See here (scroll down to item 3) for why we’ve been looking this up.