"In 1931 more than forty countries had been on the gold standard; by 1937 virtually none were. Both the United Kingdom and then the United States, the two anchors of the international monetary system, were forced to float their currencies, allowing their central banks to focus on lowering domestic interest rates without worrying about how changes in their gold reserves or capital flows would affect the exchange rate. At the same time, government deficits rose, as a result of increased public spending and collapsing revenues; this happened well in advance of the breakthrough in economic theory represented by Keynes's General Theory of Employment, Interest and Money (1936), though only two countries ran deficits sufficiently large to provide an economic stimulus."