Number of housing units with a particular house or building address number. This question is asked principally to improve census coverage. If the respondent indicated from 2 to 9 units at the address, census workers checked the number against the number of units for that address on the Bureau's address register. If the respondent's answer was higher than what WIBS shown in the address register, the building was visited to ascertain the correct number of units, thereby assuring enumeration of every unit.
Included if intended for occupancy where located. Mobile homes or trailers were counted whether mounted or on wheels.
Data users sometimes use "units at address" as a proxy for "units in structure," which is published later because it is based on a sample question. The concepts are not interchangeable, though, since some multi-unit buildings have more than one address and there is some variation in respondent interpretation of "units at address."
Similar data were collected in 1970.