If it feels like a lot of workers are going out on strike these days, thats because they are, according to a new report from Cornell University and the University of Illinois Urbana-Champaign.

The number of U.S. workers involved in work stoppages more than doubled last year, rising from 224,000 to 539,000, the universities Labor Action Tracker found. That amounted to a 141% increase between 2022 and 2023.

A handful of very large strikes helped drive the big jump in workers hitting the picket lines. Roughly 160,000 actors walked off the job as part of the SAG-AFTRA strike in Hollywood, while 75,000 nurses and other health care workers took part in the Kaiser Permanente strike that hit several states.

The overall number of work stoppages increased as well, albeit more slightly, from 433 in 2022 to 470 in 2023, the report found. More than 120 of last years strikes were smaller walkouts organized by one of two groups: either newly unionized Starbucks employees, who are battling the coffee chain for their first collective bargaining agreements , or fast food workers organized by SEIU.

Alexander Colvin, the dean of Cornells School of Industrial Labor and Relations, said the data suggested leverage was shifting away from employers and toward workers.

The strike has always been at the core of labor bargaining power, Colvin said in a statement. This rise in strike action after many years of diminished activity indicates a union resurgence that is shifting the balance of power back toward labor.