of the 21st century, partly as a result of the 1997 Asian Financial Crisis, where several nations ran out of foreign currency needed for essential imports and thus had to accept deals on unfavourable terms. The International Monetary Fund (IMF) estimates that between 2000 and mid-2009, official reserves rose from $1,900bn to $6,800bn. Global reserves had peaked at about $7,500bn in mid-2008, then declined by about $430bn as countries without their own reserve currency used them to shield themselves from the worst effects of the financial crisis. From Feb 2009 global reserves began increasing again to reach close to $9,200bn by the end of 2010. , approximately 65% of the world's $6,800bn total is held in U.S. dollars and approximately 25% in euros. The UK pound, Japanese yen, IMF special drawing rights (SDRs), and precious metals also play a role. In 2009, Zhou Xiaochuan, governor of the People's Bank of China, proposed a gradual move towards increased use of SDRs, and also for the national currencies backing SDRs to be expanded to include the currencies of all major economies. While the current central role of the dollar does give the US some advantages, such as lower cost of borrowings, it also contributes to the pressure causing the U.S. to run a current account deficit, due to the Triffin dilemma. In a November 2009 article published in Foreign Affairs magazine, economist C. Fred Bergsten argued that Zhou's suggestion or a similar change to the international monetary system would be in the United States' best interests as well as the rest of the world's. Since 2009 there has been a notable increase in the number of new bilateral agreements which enable international trades to be transacted using a currency that is not a traditional reserve asset, such as the renminbi, as the settlement currency. Balance of payments crisis A BoP crisis, also called a currency crisis, occurs when a nation is unable to pay for essential imports or service its external debt repayments. Typically, this is accompanied by a rapid decline in the value of the affected nation's currency. Crises are generally preceded by large capital inflows, which are associated at first with rapid economic growth. However a point is reached where overseas investors become concerned about the level of debt their inbound capital is generating, and decide to pull out their funds. It sometimes takes only one or two large investors