New view of marriage

In the US, one major reason for staying single is that marriage isn't viewed as it once was, and the age at which one gets married is also rising, the Census report shows.

More than half of the participants in a nationally representative sample (55 percent) said that getting married was not an important criterion for becoming an adult, according to the Census report. The same percentage also said that having a child was not an important milestone of adulthood.

"Decades ago, people often waited (or tried to wait) until marrying before having kids, having sex, or buying a home," Bella DePaulo, a social scientist at the University of California, Santa Barbara, told China Daily in an email. "Now those possibilities are readily available outside of marriage."

The author of Singled Out: How Singles Are Stereotyped, Stigmatized, and Ignored said at the same time, people start to see the positive aspects of living single, such as being free to pursue their passions, enjoying solitude and putting the people they care most about at the center of their lives, instead of a romantic partner.

Other factors contributing to the rise of one-person households include high levels of divorce, increased education that leads to more employment and better-paying career opportunities, and increased longevity and improved health at older ages.

As of 2017, the average age of a first marriage for women was about 27.5, while it was 29.5 for men. Demographers estimate that about 80 percent of Americans will marry at some point in their lives.

That's a lot lower than the 95 percent who married in the 1950s and 1960s, and it may drop somewhat more, according to Stephanie Coontz, a marriage historian and author of Marriage, a History: How Love Conquered Marriage.

"But it doesn't mean marriage is dead. It just means that marriage is no longer the only place where people make all their major financial and personal decisions, or incur obligations to others," Coontz said.

"First of all, I haven't met my Mr. Right. Also, I'm extremely responsible with my own finances – I have to pay my rent and my student loans every month," said Michelle Yu, a recent graduate of the University of Southern California, who just started her first job at a publishing company in Los Angeles. Yu has been single for more than four years.

"So, if my partner also has a ton of student loans or is in a bad financial situation, I'd rather be alone," said Yu. "Now, I can well manage my own money and I'm saving the down payment for buying an apartment in my neighborhood. I like to do that on my own pace."