The economy of the United States is the world's largest national economy and the world's second-largest overall economy, the GDP of the European Union being approximately $2 trillion larger. The nominal GDP of the United States was estimated to be $21.4 trillion in 2019, approximately a quarter of nominal global GDP. Its GDP at purchasing power parity is the second-largest in the world, behind China. It has approximately a fifth of global GDP at purchasing power parity.