The share of U.S. workers who belong to a labor union dropped from 10.5% to 10.3% in 2019, even as public approval of unions reached its highest level in years.

Just 6.2% of workers in the private sector were union members last year, a 0.2% drop compared to a year earlier, according to new data from the Bureau of Labor Statistics. The rate was essentially unchanged in the public sector, where organized labor is much stronger and 33.6% of workers are union members.

The numbers are consistent with a decadeslong decline in union membership, now hovering near an all-time low since the Labor Department started formally tracking the rate in 1983. One in 5 workers were union members that year, versus an estimated 1 in 3 at labor’s peak in the 1950s.

The raw number of union members stayed almost the same, but the growing labor force meant that unions’ collective footprint in the U.S. economy continued to shrink.

The AFL-CIO, a federation of 55 unions, said in a statement that the new statistics “don’t tell the whole story.” In 2019, workers flexed their muscles with massive strikes at General Motors and the grocery store chain Stop & Shop, the federation noted, while labor notched legislative wins in places like Nevada, where public-sector workers can now bargain collectively.

“The numbers reflect both the tremendously difficult barriers workers seeking to form a union continue to face and the unmatched resilience of working people in our desire to win bargaining power on the job,” the federation said.

Unions have complained for decades that it’s too easy for employers to quash organizing efforts by workers, with weak remedies for breaking labor law. Indeed, many nonunion workers say they would like to join a union if they could, and the public perception of unions has been steadily improving.

Polling by Gallup last year found that union favorability had hit a 16-year high, after dipping significantly around the time of the Great Recession. Of those polled, 64% said they approved of unions ― the highest rate since 2003 and among the highest in the past 50 years.

But unions face tough headwinds in Washington and statehouses around the country. An increasing number of states have passed “right-to-work” laws that forbid contracts requiring all the workers in a bargaining unit to pay union fees. That, in turn, has allowed workers to stop financially supporting unions that must continue to represent them. A landmark Supreme Court ruling in 2018 effectively made the entire U.S. public sector right-to-work.

Polling by Gallup last year found that union favorability had hit a 16-year high.

The election of President Donald Trump has also made it more difficult for some workers to unionize. Trump’s Republican appointments to the National Labor Relations Board have issued several rulings overturning earlier, union-friendly precedents. The board is also pursuing a rule that would bar most graduate students from joining unions, flipping a 2016 decision that deemed such students union-eligible employees.

Graduate programs have been fertile territory for unions in recent years (as have newsrooms such as HuffPost’s, where staffers are represented by the Writers Guild of America, East). But even though union membership among professionals increased by 90,000 to 6.27 million last year, it fell slightly as a share of the workforce. The AFL-CIO’s Department of Professional Employees said the figures showed opportunities for organizing in areas that have often been ignored, like legal services, architecture and engineering.

Unions have been lobbying Congress to pass legislation that would grow organized labor’s ranks. The PRO Act would ramp up penalties for union-busting, make it easier for unions to win first contracts, and would strengthen strike protections, among other major reforms. It is likely to pass the Democratic-controlled House but will go nowhere in the Senate under a GOP majority.