Just as American households are changing, so is the cultural composition of the United States.

As a result, builders more and more should be tailoring their home designs to meet the needs of America's growing immigrant population, which now represents 12.6 percent of the country's more than 301 million residents, according to data released today by the U.S. Census Bureau.

This data, known as the American Community Survey (ACS), notes that the total U.S. population is composed of 263.5 million native-born residents, and 38 million foreign-born people. Within that group, their tenure in the United States varies. (That's important, because the longer immigrants have lived in the United States, the more likely they are to become homeowners.) According to the Census, 16.4 million of these foreign-born residents entered the U.S. before 1990; 11.1 million arrived between 1990 and 1999; and in the first seven years of this decade, 10.5 million immigrants have made the United States their home.

They come from all over the world. Of the 38 million immigrants, 53.6 percent were born in Latin America, 26.8 percent were born in Asia, and 13.1 percent were born in Europe, with smaller percentages coming from Africa, the Pacific Islands, and North America.

As the population changes, so does the average number of people living in each owned and rented housing unit. And as the demographics change, so do the demands on the housing stock.

For the total U.S. population, the average number of people living in an owned housing unit is 2.7, and 2.42 people for the average rented unit. Among native-born Americans, the numbers are even smaller, with an average of 2.61 people living in each owned home, and 2.26 per rented unit.

But among immigrant households, which includes those who have become U.S. citizens and those who have not, the average number of people living in a house is larger. This may require builders who want to capture this group of American consumers to re-think their floor plans to accommodate larger families.

Among all foreign-born households, the average household size for an owner-occupied home is 3.49 people. (For a renter-occupied dwelling, the average is 3.11 people). The numbers are slightly lower for households that are foreign-born, but have become U.S. citizens. For those immigrants who have yet to become citizens, the numbers go up to an average of 3.85 people living in owner-occupied homes, and an average of 3.34 people living in rented units.

Among the different immigrant groups detailed by the Census, those of Latino origins have the highest average number of people living within a rented or owned household, with an average of 4.0 people living in each owner-occupied unit, and 3.55 people in each renter-occupied unit. Immigrants from Mexico have by far the highest averages, with an average of 4.4 people living in an owned unit, and an average of 3.96 people living in a rented unit.

Among European immigrants, the average owner-occupied house contains 2.55 people, while the average renter-occupied abode has 2.07 people. Among African immigrants, the average size of an owner-occupied home is 3.55 people, and the average renter-occupied home has 2.73 people living in it. For immigrant Asian households, owner-occupied units see an average of 3.46 people, while the average renter-occupied unit has 2.67 people living in it.

Ethan Butterfield is senior editor, business, at BUILDER magazine.