Quitting is in. More than 3 million Americans quit their job in December 2015, the highest number since 2006, according to data released this week by the Bureau of Labor Statistics. The quits rate, which measures how many people ended their employment out of everyone who worked each month, reached its highest level in seven years.

Economists are generally pleased when Americans feel comfortable telling their bosses it’s not working out. It is a sign of a bustling economy when people don’t stay in the same job for long periods of time, because it shows they’re confident they can find work elsewhere. But it’s possible that an even broader attitude shift is underway. The largest share of workers in the country—millennials—seem to be categorically opposed to spending their lives at one desk.

Last year, people aged-18-34 became the largest segment of the U.S. labor market, according to the Pew Research Center. The millennial workforce is expected to increase even more, Pew said, as college student graduate and new immigrants, who tend to be young, add to the 53.3 million-strong ranks of the group. Lots of them seem to be antsy. A majority of millennials to leave their jobs in the near future, according to a survey of 7,500 working, college-educated professionals born after 1982 in 29 countries released this year by Deloitte. Sixty-six percent hoped to have a different job five years from now or sooner, 44 percent said they would quit within two years, and 25 percent said they’d jump ship this year to start a new job or “do something different.” U.S. millennial workers were slightly more loyal than the global population, but not by much. Only 29 percent said they planned to stay at their current organization more than five years. The BLS does not break down the quit rate by age, so it’s hard to be sure whether young people are acting on their desire to move on.

Millennials and their older co-workers have reason to be optimistic about their job prospects. In December, job openings hit their second-highest level since the BLS began recording these figures in 2000 (July set the record, with 5.67 million openings). Employers hired more people in December than at any point since November 2006. In short, it’s a good time to be a restless worker.