WASHINGTON: Foreign students from India, China and South Korea are the major contributors to the US economy with the host country earning $21.8 billion in tuition fees and $12.8 billion in living costs from them.Over the period of 2008 to 2012, foreign students from India, China and South Korea contributed $21.8 billion in tuition fees and $12.8 billion in living costs to 118 metro areas of the US that are home to at least 1,500 students each, the prestigious Brookings Institute said in a report released on Friday.Students from the Indian cities of Mumbai and Hyderabad made a contribution of over $1.25 billion to the American economy with Mumbai sending 17,294 students, Chennai (9,141), Bangalore (8,835) and New Delhi (8,728) to the US during the five-year period, the report said.Among the foreign students in the STEM (science, technology, engineering and math) category, 31 per cent are from China, 27 per cent from India and five per cent from South Korea.The American think-tank noted that Hyderabad is the top source city of foreign STEM students in the United States and India accounts for eight of the 10 origin cities with the highest shares of their F-1 (student visa) students in STEM fields.China with nearly 2,85,000 foreign students who enter US on F-1 visas sends the largest number of foreign students to the country.Seoul, one of the largest metropolis of South Korea sent 56,000 F-1 foreign students to the US during 2008-12, the largest among other foreign cities.Beijing (49,946), Shanghai (29,145), Hyderabad (26,220) and Riyadh (17,361) also topped the list of source cities, each sending between 17,000 and 50,000, according to the report.Kathmandu with a population of just 70,000 figures in the top 10 cities having sent 10,721 students to the US.