Yes I believe they have. A number of banks have started switching, or diversifying their investments. I know Malaysia just switched to the Euro, and I do believe most Middle Eastern countries hold Euros not dollars. After WWII and up to the time we left the gold standard, US currency was the baseline currency for the entire world (The British had it before us). Even when we stopped the gold standard Central banks filled their coffers with US bills not gold; now with so much uncertainty and the high value of the Euro, this is rapidly changing. One can see what an economic advantage a country would have when its currency has such a monopoly. Another extremely troubling phenomenom is our savings rate dipped into the negatives this summer. The average American now spends more than they have. All of these are troubling signs for the future. I expect in fifteen or twenty years the bubble so to speak will burst, and we will be in major trouble. However, if this happens, the whole world will be thrown into a major recession as well--we do spend more than a third of the money in the world. Really Economics is the religion/philosophy of America, and it's foundation is of clay, as no one really understand much of anything macroeconomically other than Volcker and Friedman's display of monetary policy we are still successfully using.