The number of unmarried partners living together in the United States nearly tripled in two decades from 6 million to 17 million, 7% of the total adult population (xls).

As more unmarried couples opted to live together, their profile changed significantly, according to a new study from the U.S. Census Bureau: “Cohabitation over the Last 20 Years: Measuring and Understanding the Changing Demographics of Unmarried Partners, 1996-2017.”