"The United States is the world's biggest economy (in nominal dollars), leading trading nation (goods and services), and largest source of and destination for foreign direct investment. The U.S. output of goods and services, or gross domestic product (GDP), totaled $19.5 trillion in 2017. That is almost the combined GDP of the next three largest economies. All told, the United States, with close to 5% of the world's population, accounted for almost 25% of the world's output and more than 16% of its growth in 2017. While the United States is the world's largest exporter (goods and services combined), U.S. exports are overshadowed by the large U.S. demand for imported products. However, the level of both U.S. exports and imports of goods and services depends on many interrelated domestic and international factors, including the value of the U.S. dollar relative to other currencies, global demand for other dollar-denominated assets--including U.S. Treasury securities, and the relative strength of the U.S. and world economies. While the United States is still by far the dominant economy in the world, its relative position has shifted in the past two decades."
CRS Report for Congress, R45420
Congressional Research Service: https://crsreports.congress.gov/