Census 2000 counted 115.9 million housing units, 105.5 million of which were occupied. Both measures surpassed the 102.3 million housing units and 91.9 million occupied units recorded in 1990.

This report, part of a series that presents population and housing data collected from Census 2000, examines the number of units in a structure, the year the structure was built, the year the householder moved into the unit, and the number of people per room. The report shows how these measures vary geographically (by regions, states, counties, and large cities), by various household and housing characteristics, and over time.

The Census Bureau began collecting data on units in structure, year structure built, and person per room in 1940, the first Census of Housing. Data on the year the householder moved into the unit were first collected in 1960. Figure 1 is a reproduction of how these items were asked in Census 2000.