America is lagging.

According to an extensive survey released by the OECD Tuesday, American adults performed below average in literacy, math and problem solving when measured against their global peers.

The study -- which was conducted by Organization for Economic Cooperation and Development, an international economic organization made up of primarily industrialized member countries -- tested 166,000 adults between the ages of 16 and 65 in over 20 countries on basic reading and math skills, as well as on problem solving tasks like managing requests to reserve a meeting room on a particular date, sorting email and comparing food expiration dates on grocery store tags.

Adults in Japan led the pack in performance in all measures, but other countries including Finland, the Netherlands, and Canada significantly outperformed the U.S. in all three areas of the test.

While below average, the U.S. didn't come in last. In Italy and Spain, where unemployment remains high, adult proficiency consistently rank at the bottom of the list across generations.

Related: 3 Reasons Why You Are Failing at Problem Solving

In each of the three domains assessed, the survey defines proficiency as "a continuum of ability involving the mastery of information-processing tasks of increasing complexity." The results are represented on a 500-point scale. On average, Americans scored 270 in literacy, compared with the international average of 273 (Japan, the leader, scored 296. Italy, in last position, scored a 250). In math, the U.S. scored 253, well below the international average of 269 (Japan, again at the top, scored a 288 while Spain, at the bottom, got a 246).

While many countries including Korea and Poland show a marked jump in performance between the older generations and younger ones, in the U.S., such improvements are barely noticeable.

In math, for example, the United States performs around the average when comparing the proficiency of people aged 55 to 65, but is lowest in math among all participating countries when comparing proficiency people aged 16 to 24. As the survey points out, this isn't necessarily because performance has declined in the U.S., but because proficiency has sharply and steadily risen across generations in other countries. 

The U.S. has failed to keep up, a worrying prospect for young job applicants entering a more competitive and demanding global labor market without the necessary skills to compete.

Related: How Much Does College Matter? For Small-Business Owners, Not Much (Infographic)

And more education isn't necessarily the answer. "Italy, Spain and the United States rank much higher internationally in the proportion of 25-34-year-olds with tertiary attainment than they do in literacy or numeracy proficiency among the same age group," the survey finds. Which means it's not enough for young adults to obtain a post-secondary education; they need to learn tangible skills that schools are often failing to provide.

That the amount of school an individual receives is not an accurate measure of proficiency is driven home by this startling finding: according to the survey, "on average, Japanese and Dutch 25-34 year-olds who have only completed high school easily outperform Italian or Spanish university graduates of the same age."