U.S. workers are failing to improve the skills needed to succeed in an increasingly global economy, according to a government agency report released last month.

The National Center for Education Statistics asked 3,300 respondents ages 16-to-65 to read simple passages and solve basic math problems. What the researchers found is that literacy, numeracy and digital problem-solving ability in the U.S. have stagnated over the past few years.

Some 19% of the test-takers ranked at the lowest of three levels for literacy and 24% lacked basic digital problem-solving abilities.

Meanwhile, a shocking 29% performed at the lowest level for numeracy, the same as findings from the previous study conducted in 2012-2014. Almost one in three couldn’t correctly answer “how much gas is in a 24-gallon tank if the gas gauge reads three-quarters full.”

“These results are another signal that many Americans struggle with the most basic of math skills,” NCES Associate Commissioner Peggy Carr said in a statement. “We need to better equip Americans with the numeracy skills that they need for success, starting in middle and high school.”

There were a few bright spots among the research. Latino adults saw their overall scores improve in both literacy and digital problem solving. Some 35% ranked at the highest of three levels for the latter, up from 24% during the 2012-2014 survey period.

In addition, high school graduation rates climbed 2 percentage points to 14%, while the percentage of people with more than a high school diploma jumped 3 percentage-points to 48%.