With 2.88 people, the size of the average Hawai'i household ranks third nationally, according to Census Bureau data released today.

The state's population of 1.2 million comprises a high percentage of Native Hawaiians, Pacific Islanders and Asian groups who favor large families, said Sylvia Yuen, director of the Center for the Family at the University of Hawai'i. Also contributing to household size is Hawai'i's expensive housing market, which makes it harder for many adults to fly their parents' coop.

"Whether it is because of cultural values or because of high housing costs, we tend to have more generations living together," Yuen said. "There is a notion that we help the generations out on one hand either by supporting the grandkids or helping launch young families to give them a head start by saying, 'Come live with us and save money for a down payment,' or on the other end when parents are elderly, we bring them in or move in with them to give them support."

While comparatively high, the latest household size is down from 1990 and 2000, when it was 3.01 and 2.92, respectively.

Utah, whose largely Mormon population also encourages large families, had the highest average household size in the country, with 3.07, and North Dakota the smallest, with 2.25.

The statistics are contained in today's release of the Census Bureau's new American Community Survey, which provides more timely and updated population information every year. Without the survey, census officials said, "this type of information — historically gathered just once a decade — would not be available for communities until 2012."

The 2005 data include demographic and social information such as race, age, education, marital status, grandparents as caregivers, veterans, disability status and U.S. citizenship for 7,000 areas with a population of 65,000 or more.

Hawai'i also ranks high among households with married-couple families, 53.4 percent — fourth in the nation — and in households with at least one person age 65 and older, 28.7 percent — second behind Florida. Yuen again connected these data to the state's rich ethnic mix.

Longer life expectancy, partially due to the healthful habits of Asian residents, is one reason there are relatively more older people in local households, she said, and "in Hawai'i, more than other states, there is a tendency to keep the elderly within the family than to institutionalize them."

On the subject of marriage, Yuen said that generally, many members of Asian and Pacific Island cultures, especially older generations, have longer-lasting unions because they base their marriages "less on a notion of romance."

"There's an expectation that marriage should last through thick and thin," she said, and less desire for independence on the part of each spouse.

Hawai'i's high cost of living is likely the reason the marrying age is higher here than in most states. The median age for men at their first marriage is 28.6 years, seventh oldest in the nation, the census data reports. For Hawai'i women, the median age at first marriage is 27, sixth oldest.

About a third of males age 15 and older have never been married, according to the survey. That's the fourth-highest percentage of unmarried males in the United States. A quarter of Hawai'i women age 15 and older have never married, ranking the state 17th in that category.

The data also show that for every 100 unmarried women age 15 to 44, there are 117.9 unmarried men in that same age group.

Yuen said more young people are delaying marriage because they feel they first need to establish a solid career and financial foundation.

"With the high cost of living here, there's a feeling that 'I need to be able to support not only myself but my spouse and buy a house,' " she said.

People with a higher degree of education also tend to delay marriage, she said. The census survey shows that almost 28 percent of the Islands' population age 25 and older have a bachelor's degree (17th nationally) and that 9 percent have advanced degrees (25th nationally).

Other statistical nuggets contained in the newly released survey: