In the 1940s, most people in a relationship in the US reported meeting their partner in one of three ways: through family, friends, or school.

But starting in the 1970s, as the share of women in the workforce rose, so did the ratio of couples who started out as coworkers. From the late 1970s to the early 1990s, nearly one in five US couples reported having met in the workplace.

That percentage has since declined, according to a new study (pdf) by Stanford University sociologists Michael Rosenfeld and Sonia Hausen and Reuben Thomas of the University of New Mexico. Today, slightly more than 10% of couples say they met in the workplace, a share that has steadily declined over the past 20 years or so.

The research paper, which is currently under review for academic publication, shows the extent to which the way Americans used to meet romantic partners—through friends, in college, at church—has been supplanted by online dating. Nearly 40% of all American couples now meet their partners online.

Workplace romances have also seen a downturn since the rise of online dating. But intriguingly, according to the data (taken from the University of Michigan’s How People Meet and Stay Together survey), workplace romances started to decline a bit before relationships that started in college or church networks did.

Match.com launched in 1995, followed by JDate.com in 1997, after the share of office romances started to decline. Consider, though, that in 1991 the contentious confirmation hearings of Supreme Court nominee Clarence Thomas featured testimony of law professor Anita Hill about Thomas’s alleged sexual harassment at the office. It was a watershed moment for the ways Americans thought about sex, power, and consent at work.

It’s possible that changing attitudes towards workplace behavior after the Thomas hearings contributed to the decline in coworker romance, Rosenfeld told Quartz At Work. Still, the data doesn’t conclusively explain how much of the decline is due to online dating’s rising popularity and how much is changing culture.

And given that respondents to the survey can list more than one method for how they met, it’s possible that even coworker couples started their romance online first.