"The preponderance of that is explained by the dominance of the Mormon culture," and its focus on traditional families as the ideal, said University of Utah research economist Pam Perlich.
"But it's not all cultural. Part of it is the young age structure here," she said. For example, Perlich explains that as America is getting older on average and women outlive men, "there are a lot of older widows out there living by themselves." But not as many are in Utah by percentage because of the state's young average age one reason Utah has the nation's lowest percentage of singles living alone.
The Census Bureau's Households and Families: 2010 analysis shows a shift nationally away from traditional families, including that the percentage of households headed by married couples nationally dropped from 51.7 percent in 2000 to 48.4 percent in 2010.
"It was the first time since at least 1940 that this has fallen below 50 percent," said Daphne Lofquist, a Census Bureau statistician.
But in Utah, 61 percent of all families were headed by married-couple families, top in the nation. At the other end of the spectrum, New York was the lowest at 43.6 percent.
Utah also had the highest number of households with children 43.3 percent compared to a national average of 33.4 percent. But departing from the "Ozzie and Harriet" model, other statistics show that more Utah women than average work; still, half of Utah children under age 6 have at least one stay-at-home parent the most of any state.
The new analysis also said Utah had the most people per household at 3.1, compared with a national average of 2.58.
While Perlich said much of that data is explained by the Mormon culture, she said part of it comes because Utah has had a 20-year run of net in-migration. "And those who migrate are young people, and young people have children," she said. "It just reinforces the youthfulness and the characteristics that are already the signature of Utah demographics."
The Census analysis also said that growth in "nonfamily" households doubled by percentage compared with family households nationally between 200 and 2010, including those living alone or as nonmarried couples.
But Utah had the nation's lowest percentage of households with singles living alone: 18.7 percent, compared with a national average of 26.7.
It had the nation's lowest percentage of households headed by unmarried opposite-sex couples living together: 3.9 percent, compared with the national average of 5.9 percent. "That one is much more explained by the dominance of the Mormon culture," Perlich said. The church views couples living together before marriage as a sin.
Utah had a low percentage of households headed by same-sex couples living together: 0.4 percent. Eight states were even lower. Perlich said Utah's low rate "could be an issue of self-selection away from Utah or an issue of not disclosing."
About traditional families being more popular in Utah than elsewhere, Perlich said, "So long as we are the heart of the Mormon culture region, we will have demographics that reflect that. We're starting to become more like the rest of the nation as people move to Utah and bring their characteristics, and as people here are influenced by national trends like smaller households and women in the labor force."
The analysis also looked at the number of marriages between people of different races or ethnicities and showed that Utah was about average.
"It's definitely a growing phenomenon that people of mixed origins are finding social acceptance and self-acceptance. That's a huge change from the 1950s. That trend is unfolding in Utah at about the same rate as the nation, and I'm a little surprised by that," Perlich said.
Data show 9.4 percent of husband-wife couples in Utah are interracial or with someone of a different origin, such as Latino. It nearly matches the national average of 9.5 percent.
Among unmarried opposite-sex partners living together in Utah, 20.9 percent are interracial or of mixed origin compared with a national average of 18.3 percent.
And among same-sex couples living together in Utah, 18.3 percent are interracial or of mixed origin compared with national average of 20.6 percent.
Utah tops nation for traditional families
A new analysis by the U.S. Census Bureau shows Utah either tops or is last among states in categories relating to traditional family structure:
No. 1 • Percentage of households headed by married couples, 61 percent.
No. 1 • Percentage of households with children, 43.3 percent.
No. 1 • Most people per household, 3.1.
No. 50 • Percent of households that are singles living alone, 18.7 percent.
No. 50 • Percent of households headed by unmarried opposite-sex couples, 3.9 percent.