According to the International Monetary Fund's (IMF) Currency Composition of Official Foreign Exchange Reserves (COFER) data, the U.S. dollar was the most popular reserve currency worldwide in 2015. The euro dropped to the lowest level since 2002.

Shares of the U.S. dollar remained unchanged at 64.06% in fourth quarter of 2015, while shares of the euro declined to 19.91% from 20.21%, the lowest level since 2002.

Shares of the pound rose to 4.88% in the fourth quarter from 4.72% in the third quarter, while shares of the yen increased to 4.08% from 3.80%.