The math performance of U.S. teenagers has sharply declined since 2018, with scores lower than 20 years ago, and with American students continuing to trail global competitors, according to the results of a key international exam released on Tuesday.

In the first comparable global results since the coronavirus pandemic, 15-year-olds in the United States scored below students in similar industrialized democracies like the United Kingdom, Australia and Germany, and well behind students in the highest-performing countries such as Singapore, South Korea and Estonia — continuing an underperformance in math that predated the pandemic.

The bleak math results were offset by a stronger performance in reading and science, where the United States scored above average internationally.

About 66 percent of U.S. students performed at least at a basic level in math, compared with about 80 percent in reading and science, according to the exam, the Program for International Student Assessment, known as PISA.

The exam was last given in 2018 and measures the performance of 15-year-olds around the world, with an emphasis on real-world skills. Typically administered every three years, it was delayed a year during the pandemic. Nearly 700,000 teenagers around the world took the exam in 2022.

The results are the latest indicator of an American education system that struggles to prepare all students from an early age, with proficiency in math dropping the longer students remain in the system. National test results last year also reported greater declines in math compared with reading, a subject that can be more influenced by what happens at home and was less affected by school closures.