Give some stream of consciousness and then the answer. The US economy is fueled by abundant natural resources, a well-developed infrastructure, and high productivity. It has second highest total estimated value of natural resources, valued at $45 trillion in 2016. Americans have the highest average household and employee income among OECD nations, and in 2010 had the fourth highest median household income, down from second highest in 2007. It has been the world's largest national economy (not including colonial empires) since at least the 1890s. The U.S. is the world's third largest producer of oil and natural gas. In 2016, it was the largest trading nation in the world as well as the world's second largest manufacturer, representing a fifth of the global manufacturing output. The US also has not only the largest economy, but also the largest Industrial sector, at 2005 prices according to the UNCTAD. The US not only has the largest internal market for goods, but also dominates the trade in services. US total trade amounted to $4.92 trillion in 2016. Of the world's 500 largest companies, 134 are headquartered in the US.

Answer this question: when did the united states become the world's largest economy?
The relevant information is: It has been the world's largest national economy (not including colonial empires) since at least the 1890s.
Therefore, the answer is since at least the 1890s.