The world economy is cyclical. And if during the expansion or reduction of GDP US dollar allows other currencies of competitors to take the initiative, that during the recession pulls the blanket over himself. Blame the importance of the US economy and that a colossal role of greenbacks in international payments, foreign exchange reserves, the volume of trading on the Forex and in cross-border lending. In times of global downturns investors forget about the impact of European macroeconomic data on the euro, on the impact of monetary policy the Bank of Japan on the yen, about the pressure of political risk on the British Pound. Their eyes are turned to the single currency. US dollar.