More Together, Fewer Married As you see, the number of cohabiting male–female households in the United States has increased dramatically over the past decades. These numbers are an underestimate: Couples who do not tell the U.S. Census takers that they are living together, or who cohabit within their parents’ households, or who are same-sex couples (not tallied until 2000) are not included here. In addition, most emerging adults who are not now cohabiting may begin to do so within a few years.

Source: U.S. Bureau of the Census, 2011, and earlier years.