The most consistent aspect of family life in this country has been the high rate of marriage.

Cohabitation today takes on many different forms. The majority of people who have ever cohabited have had only one cohabiting partner, but a significant share (14%) have had a total of three or more. Just over half of cohabiters are raising children, including about a third who are living with a child they share with their partner. The nature of cohabiting relationships varies significantly by race, ethnicity and educational attainment.

Taken together, six-in-ten Americans are either married or living with a partner, a share that has remained largely unchanged since 1995.

Over the past few decades, marriage rates have declined, particularly among younger Americans. Today, 18% of adults younger than 30 are married, compared with 31% in 1995. Among adults ages 30 to 49 and those 50 and older, 62% are married – down somewhat from 1995, when marriage rates for these age groups were 68% and 65%, respectively.

At the same time, cohabitation rates have increased across all age groups since 1995, though this growth has slowed in the past decade. Among adults younger than 30, 12% are now living with an unmarried partner, compared with 5% in 1995. By comparison, 9% of adults ages 30 to 49 and 4% of adults 50 and older are cohabiting (up from 3% and 1%, respectively, in 1995).

The share of adults in cohabiting relationships has risen across all educational levels. Among those ages 25 and older with a bachelor’s degree or more, this increase in cohabitation offset the decline in marriage, and as a result the share of college graduates who are either married or living with a partner is unchanged since 1995. Among those with less education, however, the increase in cohabitation only partially counteracts the decline in marriage. Consequently, adults without a bachelor’s degree are somewhat less likely to be either married or living with a partner today than in 1995.

A majority of adults 18 to 44 have cohabited at some point in their lives

The share of adults ages 18 to 44 who have experienced both marriage and cohabitation is 35%.6 About one-in-four adults (23%) have only cohabited, 15% have only married and 26% have done neither.

Young adults – those ages 18 to 29 – are almost twice as likely to have cohabited as they are to have married (44% vs. 23%), while the largest share (48%) have done neither. Meanwhile, among those ages 30 to 44, the share that has cohabited (71%) is similar to the share that has married (73%), and 52% have both cohabited and married at some point.

There are differences by race and ethnicity as well. More than half (55%) of white adults ages 18 to 44 have ever been married, as have 48% of Hispanic adults. By contrast, only 34% of black adults have been married. When it comes to cohabitation history, differences across racial and ethnic groups are more modest: 62% of white adults have cohabited, compared with 59% of black adults and 56% of Hispanic adults. Some 41% of whites have both cohabited and been married, as have 31% of Hispanics and 26% of blacks.

At all educational levels, majorities have cohabited at some point, although the rates are lower among the most educated: About three-fourths (74%) of people with less than a bachelor’s degree have cohabited, compared with 59% of those with a bachelor’s degree or more education. Meanwhile, the share who have ever married increases with educational level, from 60% among those with a high school diploma or less to 64% for those with some college and 69% for those with a bachelor’s degree or more.7

Majorities of cohabiters across demographic groups have only lived with one partner

Those ages 18 to 29 who have ever cohabited are especially likely to have lived with only one partner in their life (73%), though a sizable minority (19%) have lived with two. Even among people ages 30 to 44 who have ever cohabited, a majority (56%) have had only one partner.

A relatively large share – 71% – of Hispanic cohabiters have lived with only one partner, and just 8% have lived with three or more. In contrast, about six-in-ten white and black cohabiters have only ever lived with one partner, and these groups are about twice as likely as their Hispanic counterparts to have had three or more partners.

There are gaps by education as well. While 72% of adults with a bachelor’s degree or higher who have ever cohabited have done so with only one partner, the same is true of only about half of those with less education.

More than half of cohabiting adults have children in the home

Married adults are twice as likely as cohabiters to be living with children they share biologically with their present spouse or partner – 70% of married adults live in this type of household, compared with 35% of cohabiters. Meanwhile, 19% of cohabiting adults are in families that include children from prior relationships only, as are 6% of married people.

The patterns also vary by educational attainment. Among cohabiters, 73% of those with a high school diploma or less education have a child in the home, compared with just 26% of those with a bachelor’s degree or more. This gap persists when looking at the proportion living with shared children: 47% of those with a high school diploma or less education live with a child they share with their current partner, compared with 17% of cohabiters with a bachelor’s degree or more. (Among married people, in comparison, the share with kids at home ranges from 83% among those with a high school diploma or less to 74% among those with a bachelor’s degree.)