Average Number of Persons Per Household, Change
During the nation’s first 200 years, the average household size fell in every decade, usually by a significant amount. During the last two decades, household size has not fallen as much, with increases in size occurring in some areas in one or the other of the last two decades. Arizona’s average household size rose marginally during the 1990s due to an influx of young immigrants, but the average slipped between 2000 and 2010. Nationally, the average fell by a small amount in both decades.