When it comes to financial literacy, U.S. teenagers’ are average — and not getting any better.

The latest data from the Programme for International Student Assessment (PISA) reveal several disturbing findings. Not only are financial-literacy levels low and not getting any better, but the differences in teenagers’ financial literacy levels are larger within—rather than across—countries.

Every three years since 2000, PISA has assessed the reading, math and science knowledge of 15-year-olds around the world. Since 2012, the program, which is headed by the Organization for Economic Cooperation and Development (OEDC,) has also measured students’ financial literacy.

When the latest findings were released in late May, it became clear that the needle on the financial literacy rate in the U.S. has not moved in the past three years. Young Americans remain entrenched in the average range. In the 2012 assessment, they scored an average of 492. In 2015, they scored 487. The average for the OECD countries in 2015 was 489.

This inertia is alarming because, if anything, American teenagers’ need for financial knowledge has grown more urgent over the past three years. Student loans have ballooned to $1.4 trillion. The average student leaves college owing more than $30,000, according to the Institute for College Access & Success. As I wrote previously, these students know little about their loans. Many have not even attempted to calculate what it takes to repay them.

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Financial decisions made early in life are consequential. Young Americans carry greater responsibility than previous generations for mapping their own financial security, not just at retirement but for an entire lifetime. And they must do so using the most developed and complex financial products and markets in the world. The latest PISA scores are clear evidence that young people do not have the savvy to manage the responsibilities awaiting them.

Knowledge gaps

American teenagers are already making financial decisions. Yet more than 20% of them have below proficient levels of financial literacy. That means it’s not just about future stakes. The present, too, is dangerous for these young people.

Amid all this, there is another finding that should give us pause: U.S. teens show greater knowledge gaps when compared with each other than when compared with their counterparts in other countries, such as Australia, Spain or Brazil.

This inequity is huge. The gap between U.S. students scoring in the top (or 90th) percentile and those scoring in the lowest (or 10th) percentile is 280 points. That equates to more than three proficiency levels. The U.S. is not alone. On average across OECD countries, the gap between the top and bottom percentiles is 285 points.

What explains those differences in the U.S.? Socioeconomic status plays a big role. Within this are parents’ education levels and occupations, home possessions (which can be used as proxies for wealth), and the number of books and other educational resources available at home. In other words, financial literacy is currently a privilege of those who can afford it.

Interestingly, only in the U.S. (and Australia) does socio-economic status explain a larger percentage of the variation in financial literacy than of the variation in other topics, such as reading performance.

The most scalable solution to this problem would be to teach financial literacy in school. We need students to be financially literate before they make financial decisions, such as whether to go to college and how much to borrow to finance that education. We also must open access to financial education to a broader group of young people. If we fail to do this, not only will our youth start on an unequal footing, but their inequality gap will continue to grow.

At the same time, we no longer should settle for “average.” The country with the most developed financial markets cannot afford to have so many teenagers who fail to understand even basic financial literacy concepts.