The data on bedrooms were obtained from answers to long-form questionnaire Item 38, which was asked at both occupied and vacant housing units. This item was asked on a sample basis. The number of bedrooms is the count of rooms designed to be used as bedrooms; that is, the number of rooms that would be listed as bedrooms if the house, apartment, or mobile home were on the market for sale or for rent. Included are all rooms intended to be used as bedrooms even if they currently are being used for some other purpose. A housing unit consisting of only one room, such as a one-room efficiency apartment, is classified, by definition, as having no bedroom.
Data on bedrooms have been collected in every census since 1960. In 1970 and 1980, data for bedrooms were shown only for year-round units. Year-round housing units are all occupied units plus vacant units available or intended for year round use. Vacant units intended for seasonal occupancy and migrant laborers are excluded. Since 1990, these data are shown for all housing units. Prior to 1990, a room was defined as a bedroom if it was used mainly for sleeping even if it also was used for other purposes. Rooms that were designed to be used as bedrooms but used mainly for other purposes were not classified as bedrooms.