In 2007, the United States had a savings rate of 14.6% of GDP, but an investment rate of 19.6%, generating a current-account deficit. By contrast, China had a fixed investment rate of 41.7% of GDP and a savings rate of 51.9%, reflected in a large surplus.
要回答这些问题，很重要的一点是理解失衡的基本动态。一国的经常项目是其投资率和储蓄率之差。2007年，美国的储蓄率为GDP的14.6%，但投资率为19.6%，故会产生经常项目盈余。与此相反，中国的固定投资率为GDP的41.7%，储蓄率为51.9%，其反映便是大量盈余。