If the UK's 2006 production was higher than France's, a fair comparison has to convert those figures to a common currency using the exchange rates prevalent at the time.  The ordering will be the same whatever currency is used.  (If X has more dollars than Y then he also has more yen, whatever the exchange rate, so long as they convert to a common currency before that spot rate moves.)  The important thing is to convert at the right time, which I believe is the time the goods and services are produced. I don't think it makes sense to reverse the order on the assumption that the UK invested the money raised from selling that output in GBP whereas France kept its proceeds in the stronger EUR.  If you are going to apply that logic then you also need to take into account the UK's higher interest rates, and possibly forward exchange rates for hedging purposes too.