The United States is the world’s greatest economic power in terms of gross domestic product (GDP) and historically has been among the world’s highest-ranking countries in terms of GDP per capita. With less than 5 percent of the world’s population, the United States produces about one-fifth of the world’s economic output.
The sheer size of the U.S. economy makes it the most important single factor in global trade. Its exports represent more than one-tenth of the world total. The United States also influences the economies of the rest of the world because it is a significant source of investment capital. Just as direct investment, primarily by the British, was a major factor in 19th-century U.S. economic growth, so direct investment abroad by U.S. firms is a major factor in the economic well-being of Canada, Mexico, China, and many countries in Latin America, Europe, and Asia.
Source: britannica.com
