Married couples are happier than “single and childless” adults, according to research from the University of Chicago and commentary from a University of Virginia sociologist.

A new paper from University of Chicago economist Sam Peltzman found that “the married population is over 30 points happier than the unmarried, and that number has hardly changed since the 1970s.”

“Marital status is and has been a very important marker for happiness,” Peltzman wrote. He based his academic paper on data from the General Social Survey.