U.S. students don’t know much about American history.

Just 13 percent of high school seniors who took the 2010 National Assessment of Educational Progress, called the Nation’s Report Card, showed a solid grasp of the subject. Results released Tuesday showed the two other grades didn’t perform much better, with just 22 percent of fourth-grade students and 18 percent of eighth-graders demonstrating proficiency.

The test quizzed students on topics such as colonization, the American Revolution and the Civil War, and the contemporary United States. For example, one question asked fourth-graders to name an important result of the U.S. building canals in the 1800s. Only 44 percent knew that it was increased trade among states.

“These results tell us that, as a country, we are failing to provide children with a high-quality, well-rounded education,” Education Secretary Arne Duncan said in a statement.

Education experts say a heavy focus on reading and math under the federal No Child Left Behind law in the last decade has led to lagging performance in other subjects.

“We need to make sure other subjects like history, science and the arts are not forgotten in our pursuit of the basic skills,” said Diane Ravitch, a research professor at New York University and former U.S. assistant education secretary.

Of the seven subjects on the national test, students performed the worst in U.S. history. Officials with the National Assessment Governing Board, which oversees the tests, say the results aren’t comparable to the other tests because different students take each exam in different years.

The scores on the history test did not vary remarkably from years past; in 1994, for example, 19 percent of fourth-grade students scored proficient or better in U.S. history.

More than 7,000 fourth-grade students, 11,000 eighth-graders and 12,000 high school seniors from a nationally representative sample took the test last year.

To be considered proficient, they had to get certain scores out of 500. For fourth-graders, the score was 243. Eighth-graders needed 294, and 12th-graders had to get a 325.

Judy Brodigan, who oversaw the elementary social studies curriculum for the Lewisville, Texas, school district for a decade, said history and social studies aren’t as much of a priority for school districts as math and reading.

She noted that many states only test history and social studies starting in middle school, which means elementary schoolers don’t get the background they need in the subject.