It may seem like Silicon Valley is populated entirely with celebrity college dropouts, but in fact, they’re the exception to the rule. Going to college pays off, and to land a job at one of the most coveted tech employers, you’ll need to stay in school.

Data analysis site Paysa looked at over 8,200 job posting and over 70,000 resumes at tech “titans” (companies worth at least $100 billion with an IPO more than 10 years ago) and “tech disruptors” (companies worth at least $10 billion with an IPO within the last 10 years) and found that employees at these companies are highly educated, not dropouts.

A disproportionate number of employees at these sought-after companies actually have advanced degrees, and one company stood out as employing the highest percentage of workers with Ph.D.s — Google.

A whopping 16 percent of positions at Google require a doctorate degree. Less than 2 percent of Americans have earned a doctoral degree and an even smaller percentage have studied topics that are relevant to Google’s work. Data visualization initiative Data USA reports that in 2015 there were only 34,002 people in the workforce with doctorate degrees in computer science — just 0.01 percent of the total U.S. population.

Snap Inc. employees are the most likely to have a master’s degree — over 36 percent of jobs at the social media company require one. (For perspective, just 9.3 percent of Americans over the age of 25 have a masters degree.)