For just the second time, women outnumbered men in the U.S. paid workforce, with their new majority buoyed by fast job growth in health care and education over the past year, as well as the tight labor market.

At first glance, the shift is tiny and easy to miss: Women worked 50.04 percent of payroll jobs in December, up from 49.99 percent the prior month. But the figure reflects a larger, ongoing trend. Of the 145,000 jobs picked up in December throughout the economy, women won most of them — 139,000, according to Labor Department data.

“Why is today a milestone? It’s a milestone because it’s really heralding the future and not just telling us where we are today,” said Betsey Stevenson, a professor of public policy and economics at the University of Michigan and an economic adviser in the Obama administration.

Indeed, women’s share of the workforce has been growing steadily for the past few years. Zooming out, looking at all workers, including farmworkers and those self-employed, men still outnumber women. But women have been joining the workforce at a faster pace than men since 2018. Economists say this narrowing in the gender gap comes as women have been getting college degrees in larger numbers than men, which has radiated out to the job market as they reach higher ranks in the office.

“As women get into more senior positions, it creates more space to hire more women and brings more equality into management decisions,” Stevenson said. “It’s one of those things that’s self-reinforcing and keeps on going.”

Industries that have long attracted larger numbers of women, such as education and health care, are growing at a much faster pace than male-dominated industries such as manufacturing and construction. At the same time, with the unemployment rate hovering at a 50-year low, just 3.5 percent, all workers have more leverage than ever to negotiate their own salaries and work schedules, which is often a top priority for parents.

The first time the share of women in the paid workforce crossed over 50 percent was back in early 2010 in the aftermath of the Great Recession, which was a time of tremendous volatility in the labor market. Men were losing jobs at a much greater pace, as industries such as manufacturing and construction struggled. That left more women working while men hoped to return.

Now, there’s a more permanent dynamic in play. Women are dominating sectors that are growing the fastest. Health care in particular was one of a few sectors that added more jobs in 2019 than 2018, Stevenson said. Also, jobs in education and health services outnumber jobs in male-dominated goods production sectors; mining, construction, transportation and warehousing saw a slowdown in hiring last year. And women still dominate service-sector jobs, which is 84 percent of non-farm payroll jobs in the country.

A big difference between now and 10 years ago is that women today are getting a boost from technology that has opened the door to jobs that used to be considered men-only. Julia Pollak, labor economist at ZipRecruiter, pointed to transportation jobs: For decades, cabdrivers were almost exclusively male. But apps and other platforms helped bring women into the driver’s seat.

“Women who might have felt less safe as taxi drivers before, waiting around for some man to wave them down, now have the protection of an app where people can be identified if something goes wrong,” Pollak said.

Plus telecommuting and parental leave policies are becoming more common in the private sector, as employers are competing to hire and keep talent in this hot jobs market.

Stacey Ferguson, 42, worked in corporate law and government for 10 years before she left to start her own digital marketing company in 2012. A year and a half ago, she took a marketing job that allowed her to work remotely full-time. Ferguson, who has three kids and lives in suburban Maryland, said her entire team works out of the office, which helps cement a culture where “everyone is in the same boat.”

That’s a stark shift from her time practicing law, which wasn’t as family-friendly, she said. Plus, cultural norms around working from home have drastically changed over the years.

“The biggest thing is the mind-set,” Ferguson said. “Trying to work remotely 10 years ago was received very differently than it is now. … There’s just a general loosening of the typical corporate guidelines and restrictions.”

Liz Cook just nabbed a full-time job in November, working as a data analyst for the Mom Project, which helps women workers find jobs. Cook left her job as a prosecutor in 2011 to spend more time with her children. And until recently, she’d had trouble getting back into the workforce with the gap on her résumé, despite having a law degree.

“Perhaps [employers] are more willing to overlook gaps in résumés, or there’s a cultural shift and they’re more willing to bring moms or women in,” said, Cook, 36, who needed to return to work to pay off student loans.

The data on women in the workforce was tucked into an otherwise steady jobs report, as the unemployment rate remained at a strong 3.5 percent, unchanged from November and at a 50-year low. The Department of Labor data showed gains in retail and health care, thanks to women, while mining jobs slipped. Manufacturing jobs, which analysts have been closely monitoring during Trump’s protracted trade war, changed little in December.

The December jobs report continued a 10-year streak of strong labor market growth since the Great Recession that has spanned two administrations. Larry Kudlow, President Trump’s director of the National Economic Council, touted the continued strong jobs numbers, acknowledging the growth of women in the workforce.

“This stuff will translate in the election, I’m surprised the Democrats are so pessimistic painting a picture of a deep recession,” Kudlow said in an interview. “The key point here is 3.5 percent unemployment continues, and that is a very low number historically and shows you still have a healthy economy and healthy job market.”

Despite the job gains for women, wage growth overall has continued to be ho-hum. Average hourly earnings rose by a mere 0.1 percent in December, meaning over the past year, wage growth is at 2.9 percent.

Economists say wages are not growing as fast as they should be, especially for those who aren’t seeing a boost from state and local minimum wage increases. Many businesses are still pulling back on investment and say the truce with China does little to assuage their anxiety.

Democratic leaders and presidential hopefuls have cautioned that Trump’s economic and trade agenda could eventually stymie the growth.

Diane Swonk, chief economist for the accounting firm Grant Thornton, said the decent job numbers but disappointing wage growth reflects “an economy where you can get a job, but it’s harder to get a raise.” Swonk said it’s possible wage growth figures for the start of 2020 could be ever harsher because wages for 2019 peaked in February.

Looking at employment gains over the past 12 months, the average monthly jobs gains were 176,000, compared with 223,000 in 2018. But Mark Hamrick, senior economic analyst for Bankrate, said the decrease shouldn’t come as a surprise. December’s figures didn’t reveal “anything that rocked our world,” he said.

“Expansions don’t last forever, and this one probably is getting a little long-toothed, but it’s not on life support,” Hamrick said.

The jobs figures come as Trump touts the economy’s strength as one of his administration’s top achievements. In addition to the strong labor market, the Dow Jones industrial average has gained about 45 percent since Trump took office, and fears of an imminent recession have largely faded. The Federal Reserve cut interest rates three times last year, helping to sustain an 11-year-old economic expansion. But the Friday jobs report gives the Fed good reason to keep their current policy as is, meaning any more cuts are less likely.

More than two decades ago, Rachel Higgins left her job at IBM to stay at home with her children. She was ready to go back to work by the time her son went to college and learned about ReacHIRE, which partners with companies to help women return to work. In April 2019, Higgins landed an internship with the software and professional services firm Lionbridge.

She was hired full-time in September.

“Here I am after 21 years without working,” said Higgins, 53. “I’m walking through the doors of major global companies and giving a presentation. I’m back! I’m back, baby!”

Andrew Van Dam and Jeff Stein contributed to this report.