Those who wring their hands about the mediocre performance of U.S. students on international math and reading tests have another worry: The nation's grown-ups aren't doing much better.

A first-ever comparison of adults in the United States and those in other democracies found that Americans were below average in skills needed to compete in the global economy.

The survey, released Tuesday, measured the literacy, math and computer skills of about 5,000 U.S. adults ages 16 to 65 and compared them with similar samples of adults from 21 countries in the Organization for Economic Cooperation and Development.

The Americans are "decidedly weaker in numeracy and problem-solving skills than in literacy, and average U.S. scores for all three are below the international average and far behind the scores of top performers like Japan or Finland," said Jack Buckley, commissioner of the National Center for Education Statistics, which is part of the U.S. Education Department.

As for literacy, adults in the United States trailed those in 12 countries and outperformed adults in five others. The top five countries in literacy were Japan, Finland, the Netherlands, Australia and Sweden.

U.S. adults did worse in mathematics, where they trailed 18 countries and beat just two — Italy and Spain.

And in the category of "problem-solving in technology-rich environments," or digital skills, U.S. adults lagged behind their counterparts in 14 countries.

Among the most educated test-takers — those with graduate or professional degrees —Americans scored higher than average in literacy but lower than average in math and digital skills.

The achievement gap between white test takers and black and Hispanic test takers, a stubborn problem in U.S. K-12 public education, showed up in the adult survey. There were significant differences in test scores between whites and minorities.

WASHINGTON POST