A household includes all of the people who occupy a housing unit. A housing unit is a house, an apartment, a mobile home, a group of rooms, or a single room occupied (or if vacant, intended for occupancy) as separate living quarters. Separate living quarters are those in which the occupants live separately from any other people in the building and that have direct access from the outside of the building or through a common hall. The occupants may be a single family, one person living alone, two or more families living together, or any other group of related or unrelated people who share living quarters.

In 100-percent tabulations, the count of households or householders always equals the count of occupied housing units. In sample tabulations, the numbers may differ as a result of the weighting process.

The data on relationship to householder were derived from the question "How is this person related to Person 1," which was asked of Persons 2 and higher in housing units. One person in each household is designated as the householder (Person 1). In most cases, this is the person, or one of the people, in whose name the home is owned, being bought, or rented. If there is no such person in the household, any household member 15 years old or over could be designated as the householder (that is, Person 1).

Households are classified by type according to the sex of the householder and the presence of relatives. Two types of householders are distinguished: family householders and nonfamily householders. A family householder is a householder living with one or more people related to him or her by birth, marriage, or adoption. The householder and all of the people in the household related to him or her are family members. A nonfamily householder is a householder living alone or with nonrelatives only.

A person having origins in any of the original peoples of Europe, the Middle East, or North Africa. It includes people who indicate their race as White or report entries such as Irish, German, Italian, Lebanese, Near Easterner, Arab, or Polish.

The data on the Hispanic or Latino population were derived from answers to a question that was asked of all people. The terms "Spanish,""Hispanic origin," and "Latino" are used interchangeably. Some respondents identify with all three terms while others may identify with only one of these three specific terms. Hispanics or Latinos who identify with the terms "Spanish,"" Hispanic," or "Latino" are those who classify themselves in one of the specific Spanish, Hispanic, or Latino categories listed on the questionnaire ("Mexican,""Puerto Rican," or "Cuban") as well as those who indicate that they are "other Spanish/Hispanic/Latino." People who do not identify with one of the specific origins listed on the questionnaire but indicate that they are "other Spanish, Hispanic, or Latino" are those whose origins are from Spain, the Spanish-speaking countries of Central or South America, the Dominican Republic, or people identifying themselves generally as Spanish, Spanish-American, Hispanic, Hispano, Latino, and so on. All write-in responses to the "other Spanish/Hispanic/Latino" category were coded.

Origin can be viewed as the heritage, nationality group, lineage, or country of birth of the person or the persons parents or ancestors before their arrival in the United States. People who identify their origin as Spanish, Hispanic, or Latino may be of any race. Some tabulations are shown by the origin of the householder. In all cases where the origin of households, families, or occupied housing units is classified as Spanish, Hispanic, or Latino, the origin of the householder is used. (See the discussion of householder under "Household Type and Relationship.")

If an individual could not provide a Hispanic origin response, their origin was assigned using specific rules of precedence of household relationship. For example, if origin was missing for a natural-born daughter in the household, then either the origin of the householder, another naturalborn child, or spouse of the householder was assigned. If Hispanic origin was not reported for anyone in the household, the Hispanic origin of a householder in a previously processed household with the same race was assigned. This procedure is a variation of the general imputation procedures described in "Accuracy of the Data" and is similar to those used in 1990, except for Census 2000 race and Spanish surnames were used to assist in assigning an origin (see the "Comparability" section below also).