The drop in F-1 student visas for Chinese nationals represents a 99% decline—a decrease larger than the one seen among international students outside of China, according to Nikkei Asia.

Around 370,000 Chinese nationals studied in the U.S. during the 2018–2019 school year; they accounted for more than a third of the entire international student population in the U.S., according to the Institute of International Education. The U.S., in turn, is the No. 1 destination for Chinese students studying abroad—those who study in the U.S. represent more than half of all overseas Chinese students.

But the Trump administration’s increasingly unfriendly immigration policies toward Chinese students and now the COVID-19 pandemic appear to be chipping away at those figures.

Chinese students are enrolling in the U.S. at a much slower rate than in the past. For the 2015–2016 school year, the number of Chinese students enrolled in U.S. schools rose 8.1%; for the 2018–19 school year, it rose 1.7%. Overall, new international student enrollment at U.S. universities has declined for the past three years.

The drop-off poses a significant financial threat to U.S. universities, since most international students pay full tuition compared to their American peers, who often receive financial aid. Chinese students alone paid an estimated $15 billion in tuition payments to U.S. colleges in the 2018-2019 school year.

In recent years, the Trump administration has erected barriers to Chinese nationals studying in the U.S. as part of a wider political dispute with China that has often devolved into tit-for-tat retaliations across trade, technology, and immigration.

In September, the U.S. Department of State revoked 1,000 student visas awarded to Chinese nationals, saying the students and researchers in question had ties to the Chinese military. In 2019, the U.S. restricted visas for Chinese students who researched any technology that could have national security applications, and in 2018 the administration cut the visa length for Chinese graduate students in high-tech fields from five years to one.

The U.S.’s handling of the pandemic is another enormous deterrent for Chinese students. Many international students attending U.S. colleges opted to stay in their home countries for remote fall semesters—either because coronavirus travel restrictions prevented them from traveling to the U.S., or because they were unable to obtain visas.

Some universities adapted to the situation.

At Pennsylvania State University, for instance, most international students are attending classes remotely this semester, and 5,080 of the 11,000 international students hail from China. The university arranged for some of its students in China to attend in-person classes in Shanghai at one of the college’s affiliated study-abroad centers.

“Since we knew that some new students wouldn’t be able to make it to the U.S. because of visa restrictions, we started thinking, ‘What would it look like to offer students a residential experience in their own country?'” a Penn State representative said in a university press release.

In addition to hurting universities, the increased number of Chinese citizens opting to study abroad in countries outside the U.S. could result in a significant hit to the U.S. economy generally. International students contributed almost $41 billion to the U.S. economy in 2019, according to the NAFSA Association of International Educators.