After three years of declining employment, more teenagers are finally getting summer jobs.

The number of 16 to 19-year-olds working in June surged by nearly 700,000, the biggest job gain for that age group since 2013, according to a new analysis from Challenger, Gray & Christmas. Despite a decline in in May, summer hiring for teenagers is now outpacing 2015.

“Teenagers may be benefitting from a resurgence in the fast-food industry,” CEO John Challenger said in a statement. “Unlike traditional retailers, which appear to be closing locations as more people shop online, food establishments are exploding.”

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Burger chain Sonic, for example, is in the midst of plans to construct 1,000 new stores over the next decade, and Chick-Fil-A has plans to open new stores in more than 30 states.

Since May, employers have hired 847,000 teenagers, a 7.1 percent increase from last year, and overall teen employment is up 4 percent to the highest June employment level since June 2009.

The shift is also one more sign of recovery in the U.S. job market as teenagers are facing less competition from older workers forced into underemployment in entry-level jobs.

Regardless of the reason, more teens working is a good thing for the economy and for the teens themselves. A December 2014 paper in the Journal of Labor Economics found that working teens are have lower levels of mortality or incarceration.