Here is a look at the percentage of teens employed over time.
The graph below shows the employment-population ratio for teens (16 to 19 years old) since 1948.
The graph is Not Seasonally Adjusted (NSA), to show the seasonal hiring of teenagers during the summer.
A few observations:
1) Although teen employment has recovered some since the great recession, overall teen employment had been trending down. This is probably because more people are staying in school (a long term positive for the economy).
2) Teen employment was significantly impacted in 2020 by the pandemic.
3) A smaller percentage of teenagers are obtaining summer employment. The seasonal spikes are smaller than in previous decades.
4) The decline in teenager participation is one of the reasons the overall participation rate has declined (of course, the retiring baby boomers is the main reason the overall participation rate has declined over the last 20+ years).