With a GDP of over $23 trillion in 2021, the United States has the world's largest economy, according to the latest available data from the World Bank. Yet, the U.S. falls behind such countries as Israel and Korea when it comes to how much is spent on research and development (R&D) in proportion to GDP. For example, Israel and Korea spend 5.56% and 4.93% of their GDP on R&D compared to the U.S.’ 3.46%.