The economy is roaring. So why are more workers striking?

Labor strikes are back.

Forty-six thousand GM employees made headlines last year by halting work to ask for stronger protections and better healthcare. But it wasn’t just the automaker — there has been a strike renaissance over the past two years.

The largest job action of 2019 involved 92,700 North Carolina public school teachers who walked the picket line on May 1, International Workers’ Day. Next was GM’s six-week strike, followed by a two-day stoppage by 36,400 West Virginia teachers and a six-day strike by 33,000 Los Angeles teachers, according to the Bureau of Labor Statistics.

That’s a far cry from 2017, when only 25,000 workers participated in major strikes during that entire year, the second lowest annual number since 1947.

Two factors likely are driving workers to stage walkouts en masse, according to the Economic Policy Institute, a nonprofit think tank whose research focuses on trends involving working people. Employees are well aware that if they lose their jobs for striking they’re likely to find another quickly. And employees aren’t getting the wage gains that a tight labor market normally brings.

“[It’s] people kind of looking around and saying, ‘Oh my God, we’re 10 years into this recovery. The unemployment rate is 3.6%. Why am I not seeing decent wage increases?'” said Heidi Shierholz, one of the authors of EPI’s analysis and a former Department of Labor chief economist in the Obama administration.

In both 2018 and 2019, at least 425,000 workers took part in large-scale walkouts, marking a 35-year high for the number of employees involved in major strikes over a two-year period, according EPI’s analysis of Labor Department data. The protests surged even though the unemployment rate hasn’t been this low in 50 years and the economy keeps adding jobs at a higher-than-expected clip.

US government data focuses on “major work stoppages,” or strikes that involve 1,000 or more workers and that last at least one shift.

The recent figures don’t compare to 20th century job actions, of course. In 1949, more than 2.5 million workers were involved in such efforts, according to the Labor Department. During one 1919 protest, as many as 365,000 steelworkers walked off their jobs, AFL-CIO statistics show. And in 1970, a strike of more than 150,000 postal workers forced the government to assign 24,000 military members to deliver the mail, according to the United States Postal Service.

However, the recent rise in job actions marks a “meaningful break,” according to EPI.

The GM strike may have been one of the most talked about job actions of last year, although in the end the union wasn’t able to win some of their key demands. Some of the 270,000 workers in educational services who staged walkouts in 2019 had greater success.

Los Angeles teachers didn’t get everything they wanted but secured a 6% raise and smaller class sizes, while West Virginia teachers stopped a bill that would have used public funds to fund new charter and private schools.

Shierholz, who serves as EPI’s policy director, said these measures had a “positive effect on the wages and working conditions of the workers that are engaging in them.”

“I do think that successful strikes in one place can give workers [elsewhere] more confidence in their ability to have a successful strike,” said Shierholz, whose policy team supports a “worker-first” approach.

Walkouts are more common in a tight labor market, Shierholz added. “I do think it’s likely we’ll continue to see this kind of activity,” she said.