New York CNN —

If you want to find the most new union members, don’t go to a Starbucks or an Amazon warehouse, despite the high profile organizing wins unions have achieved with those employers in recent years. Head to college and university campuses.

The Dartmouth College men’s basketball team achieved a significant milestone last week when they became the first college athletes to vote to join a union. But they are only a small part of a much larger trend – that of college and graduate students voting in big numbers to join unions in their on-campus jobs.

Organizing vote wins in higher education have added more new union members than in any other sector of the economy in recent years, said Christian Sweeney, deputy organizing director at the AFL-CIO.

“It’s been happening for a while,” he said. “It’s young people saying we’ve got to protect our interests here. It’s really very much grassroots driven.”

Romeo Myrthil, second from left, and Cade Haskins, third from left, stand with fellow Dartmouth teammates during the game against Columbia University. Laura Oliverio/CNN

The National Labor Relations Board, which oversees union representation votes for private sector employers such as Dartmouth, reports 38 separate elections in just the last two years, including the Dartmouth basketball vote, bringing 41,500 student employees into various unions. And that doesn’t include additional students at state schools who are joining unions, but operate under a different labor law.

For example, student assistants at the California State University system voted overwhelmingly to join a union last month, bringing 20,000 into the CSU Employees Union.