In an April 2017 report, the U.S. Census Bureau examines changes in young adulthood over the last 40 years. The study looks at how the economic and demographic characteristics of young adults (ages 18 to 34) have changed from 1975 to 2016.

The report defines adulthood as a period in life associated with common experiences and the achievement of particular milestones, such as living independently of parents, working full-time, getting married, and having children.

This puts some recent changes in perspective: In 1975, 45% of young adults (ages 25 to 34) had completed four specific milestones — lived independently of their parents, had ever married, lived with a child, and were in the labor force — compared with only 24% of 25- to 34-year-olds in 2016.

The report also reveals that while educational and economic accomplishments are considered important milestones of adulthood by most of today’s Americans, marriage and parenthood rank much lower.

Education and economic stability rated most important

The highest-ranked milestone of adulthood by Americans today is completing a formal education: More than 60% of Americans believe that doing so is extremely important. Ranked second is working full-time (52%), followed by the ability to support a family financially (50%).

More young adults today have achieved this educational milestone compared with their counterparts 40 years ago. For example, less than one-fourth of 25- to 34-year-olds had a college degree in 1975, compared with more than one-third in 2016.

Marriage and parenthood are delayed milestones

Over half of Americans believe that getting married and having children are not important to becoming an adult, but this does not mean they plan to forgo these milestones altogether. Instead, getting married and having children are occurring later in life.

Whereas eight in 10 young adults in the mid-1970s had married before age 30, this milestone isn’t reached today by the same proportion of Americans until their early 40s. Similarly, more than two-thirds of women in the mid-1970s were mothers by the time they were ages 25 to 29, but today that proportion is not reached until ages 30 to 34.

Living independently is less important

Only about one-fourth of Americans rank moving out of a parent’s home as an extremely important adult milestone. So it’s not surprising that the number of young adults living independently has declined. In 1975, 26% of young adults (ages 18 to 34) were living in their parents’ home, compared with 31% in 2016.

Also noteworthy is that in just a decade, living arrangements changed dramatically. In 2005, a majority of young adults lived independently in their own households (either alone, with a spouse, or with an unmarried partner) in 35 states. By 2015, though, only six states had a majority of young adults living independently.

Not completing a formal education and lack of a steady job are contributing factors to the decline in young adults living independently. Young people who still live with their parents today are far less likely than their peers to have a college degree or a full-time job. Of young adults (ages 25 to 34) today who are living independently, 41% have a bachelor’s degree and 64% have a full-time job. Not surprisingly, young people living independently also tend to have higher incomes: More than half of older millennials living in their own households earn $30,000 or more in income, compared with only about one-third of their peers who live with roommates and one-fourth who live with their parents.

Of young adults (ages 25 to 34) living in their parents’ home today, one in four are not attending school or working. Often they are older millennials who have only a high school education. This group typically faces challenges such as the loss or unavailability of a job, unaffordable housing rates, and child-rearing responsibilities.

The shifting paths of young adulthood

Over the last 40 years, the milestones of adulthood have remained largely the same, but the importance and timing of these milestones have changed. Young adults today are less focused on marriage and parenthood in their 20s and early 30s and are more concerned about establishing financial security by finishing school and gaining work experience. More of them have college degrees and full-time jobs than their counterparts did in 1975, but fewer own their own homes. As a result, young people today often delay establishing a household and settling down with a family until they are able to support themselves financially.