The graph here is from the EPI article Class of 2023: Young adults are graduating into a strong labor market by Elise Gould, Jori Kandra, and Katehrine deCourcy (5/3/2023). They note:
Over the last 40 years, employment among young people has declined by about 7 percentage points while enrollment in school has increased by about 13 percentage points, as shown in Figure B.
These are true statements but do they accurately reflect the trends? Not really, but they clarify this a paragraph later:
Between 1986 and 2012, young people increased their enrollment in high school, college, or university by 19 percentage points from 36% to 55%. Enrollment softened a bit in 2013, then mostly held steady, softening slightly again in the pandemic. As of March 2023, 51.8% of young adults are enrolled in school.
The article is worth reading and there are three other graphs. All the graph have a data link.