Source: U. S. Census Bureau, American Community Survey, 5-Year Estimates. Updated every year. http://factfinder2.census.gov
Housing units in multi-unit structures are units in structures containing 2 or more housing units. Some tabulations further categorized them as units in structures with 2, 3 or 4, 5 to 9, 10 to 19, 20 to 49, and 50 or more units. Excluded from this category are single-family homes, mobile homes, and occupied living quarters that do not fit in the previous categories, such as houseboats, railroad cars, campers, and vans.
Units in structure was determined for both occupied and vacant housing units. A structure is a separate building that either has open spaces on all sides or is separated from other structures by dividing walls that extend from ground to roof. In determining the number of units in a structure, all housing units, both occupied and vacant, are counted. Stores and office space are excluded. The statistics are presented for the number of housing units in structures of specified type and size, not for the number of residential buildings.
The percentage shown is calculated by dividing the number units in multi-unit structures by the total number of housing units.
Scope and Methodology:
These data are collected in the American Community Survey (ACS). The data are estimates and are subject to sampling variability. The data for each geographic area are presented together with margins of error at factfinder2.census.gov. The data are period estimates, that is, they represent the characteristics of the housing over a specific 60-month data collection period.