This simple question is being asked by many people who have concerns about the growing power of many developing countries that they will surpass the U.S. economy very soon.
I want to answer by a simple graph.
This graph shows the GDP share of six economies to the world GDP (%) from 1990 to 2014. I compared GDP share of U.S., European Union, and BRICs to the global GDP in the graph. I used the data from World Development Indicator (World Bank, 2016). This series of GDP is calculated using PPP technique at constant 2011 international dollars. PPP GDP is gross domestic product converted to international dollars using purchasing power parity rates. An international dollar has the same purchasing power over GDP as the U.S. dollar has in the United States (Detail: http://data.worldbank.org/indicator/NY.GDP.MKTP.PP.KD). This technique can eliminate the effect of inflation in different countries.
BRICs is a group of big developing countries that have potential to grow and some analysts and economists expect that they can surpass the U.S. economic power very soon. BRICs consists of B- Brazil, R-Russia, I-India, and C-China.
EU has the biggest share of world GDP (17%) while U.S.share is around 16.02% in 2014. China’s GDP share is growing very fast, from under 5% in 1990 to 16.57% in 2014.
Now China has higher share of world GDP than the U.S.
Other countries in BRICs have only slightly increased in their share of the world GDP in the past 24 years.
Therefore, comparing the GDP share (PPP), the U.S. is losing economic power to China.
– -That is my simple answer from this graph.
Please note that if you consider ‘economic power’ in term of nominal GDP, the competitiveness, the quality of higher education system, number of innovations or quality of life , you might see different pictures.