No way their strength reflects the strength of their country's economy. Some east countries are the leaders of the list but you have to consider that they are heavily dependant on the oil price and demand, so it makes their economy potentially vulnerable. My country's currency is valued significantly higher than Russia's or Turkey's currency but the economy of these countries are much more powerful than the economy of my country. It's also clear from the list that Kuwait's economy can't be stronger than USA's economy. The US economy is number one and then come other countries.