The unemployment rate slipped for Black and Hispanic workers in April, but remained stable for Asian American workers.

The U.S. unemployment rate inched down to 3.4% last month, according to the U.S. Bureau of Labor Statistics. The number not only marked a decrease from 3.5% in March, but it also tied for the lowest rate since 1969.

Unemployment dipped sharply for Black workers, declining to 4.7% in April from 5% in the previous month. Similarly, the unemployment rate among Hispanic workers declined to 4.4% last month from 4.6%.

For Asian American workers, the unemployment rate held steady at 2.8%, as it was in March.

“Unemployment rates remain low across the board and historically low for Black workers,” said Valerie Wilson, director of the Economic Policy Institute’s program on race, ethnicity and the economy.

With the overall unemployment rate under 4%, the difference in rates between racial demographic groups is also narrowing, she added.

A closer look at the labor force participation rate — a measurement of the number of people seeking work — shows an underlying factor behind the falling unemployment rate for Black workers in this latest report.

“The Black unemployment rate fell for quirky reasons in a way,” said AFL-CIO chief economist William Spriggs. That’s because the labor force participation rate for Black workers declined in April, he said, dropping to 63% from 64.1% in March. For Black men, the rate slipped to 67.8% from 70.5%.

When that finding is placed alongside the declining unemployment rate, it suggests there are unemployed workers who either stopped looking for a job or didn’t get one at that point in time.

“It’s kind of a weird mixed message,” said Wilson. “But again, looking at the longer-term trend, it’s still fairly stable and steady with what we’ve seen in the last several months.”

Longer-term trends also show a slight increase in the labor force participation rate for Asian American populations, which was 64.9% in April — the same as in March. A year ago, the participation rate for this demographic group was 64.5%. “This is also a sign of continued job growth as more people enter the labor market,” said Wilson.

April’s payrolls report showed huge gains in the health care and social assistance industry — an increase of more than 64,000 jobs — while government positions swelled 23,000.

Growth in those jobs is a positive development for women and people of color in particular, said Spriggs, as they tend to hold managerial positions in the health and public service industries.

“The fact that those sectors are doing well and still hiring, that’s good news for issues of equity,” he said.

— CNBC’s Gabriel Cortes contributed reporting.