Data from the Institute of International Education showed that compared to the 2013–14 academic year, the number of foreign students enrolling in American colleges and universities peaked in 2015–6, with about 300,000 students, before falling slightly in subsequent years. Compared to the 2017–18 academic year, 2018-19 saw a drop of 1% in the number of foreign students. This is a concern for institutions that have become reliant on international enrollment for revenue, as they typically charge foreign students more than their domestic counterparts. As of 2019, these were the first downturn in a decade. However, the number of foreign graduates staying for work or further training has increased. In 2019, there were 220,000 who were authorized to stay for temporary work, a 10% rise compared to fall 2017. Top sources of students studying abroad in the United States were China, South Korea, India, and Saudi Arabia (in that order). While the number of Chinese students on American soil has fallen noticeably—due to a variety of factors, such as reported difficulty of obtaining a U.S. visa amid the ongoing Sino-American trade war, more competition from Canada and Australia, and growing anti-Chinese sentiments due to concerns over intellectual property theft—students coming from elsewhere in Asia (though not South Korea and Japan), Latin America, and Africa have gone up. In particular, the number of Nigerian students climbed 6% while those from Brazil and Bangladesh rose 10%. The most popular majors have shifted, with business, an academic subject extremely popular among Chinese students, falling by 7% in the 2018–19 academic year. Meanwhile, mathematics and computer science jumped 9%, replacing business as the second most popular majors after engineering.