WASHINGTON (NewsNation) — More than 400,000 undocumented students — or nearly 2% of all college students in the country — were enrolled in U.S. colleges and universities in 2021, according to U.S. Census data.

That 2%, however, reflects a 4.2% decrease from 2019. Experts have cited the COVID-19 pandemic as well as legal challenges to the Deferred Action for Childhood Arrivals (DACA) program.

“These students are the future talent and workforce potential of our country,” said Steven Hubbard, senior data scientist at the American Immigration Council. “Their pursuit of higher education will lead to reduced dropout rates, increased college enrollment, and greater economic contributions, all while enhancing our country’s economic competitiveness.”

The DACA program marked its 11th anniversary in June with little fanfare. But more and more Dreamers are falling out of DACA eligibility because of their age, and many who are technically eligible can’t sign on because of a legal challenge against the program.

The legislative logjam that’s persisted in the decade since has left DACA as the only means for Dreamers to formally participate in the economy and receive protection from deportation.

NewsNation affiliate The Hill contributed to this report.