In 1975 and 2009, China's GDP per capita grew at an average rate of 7.9% per year whereas GDP per capita in United States grew at an average rate of 1.8%. In 2009, U.S. GDP per capita was $41, 099 and Chinese GDP per capita was $7, 634. Assuming that the two countries continue to grow at these rates, in what year will China overtake the United States in terms of GDP per capita?