The portion of American households made up of married couples with children under 18 fell to 20 percent from 40 percent from 1970 to 2012, the Census Bureau said Tuesday as it detailed other fundamental changes in family life.

The share of people living alone, meanwhile, rose 10 percentage points, to 27 percent.

The analysis also found that the recession profoundly affected American families from 2005 to 2011, resulting in a 15 percent decline in homeownership among households with children and a 33 percent increase in households where at least one parent was unemployed.

The recession also saw more mothers enter the work force and an increasing dependence on food stamps.

The number of households with an unemployed parent soared by 148 percent in Nevada and by more than 50 percent in California, Colorado, Connecticut, Florida, Hawaii, New Jersey and North Carolina in those years.