A question on the sex of individuals has been asked of the total population in every census.

Calculated as the value which divides the age distribution into two equal parts, one-half the cases falling below this value, one-half above. Median age is computed from the age intervals or groupings shown in the particular tabulation, and thus a median based on a less detailed distribution may differ slightly from a corresponding median for the same population based on a more detailed distribution. If the median falls in the terminal category, e.g., 75 years and over, the median is shown as the initial age of the category with a plus sign, e.g., 75+.

In previous censuses, undercoverage of the population has been associated with age. Young adults, especially Black males, were missed at a higher rate than other segments of the population. The same is true of centenarians.

Age data have been collected in each census since 1790. Counts in 1970 and 1980 for persons 100 years old
and over were substantially overstated.

See also: "Age of Householder".

Persons who indicated "Mexican, Mexican-American, Chicano," or wrote in an entry such as "La Raza."

Persons who indicated "Puerto Rican" or wrote in an entry such as "Boricua."

Persons who indicated "Cuban."

Persons who filled the circle for "other Spanish/Hispanic"; or persons who wrote in an origin or descent associated with Spain, the Dominican Republic, or any Central or South America country except Brazil or a nonspecific Spanish group such as "Spanish surnamed" or "Spanish speaking."

Preliminary evaluations of 1980 census data suggest some limited misreporting of Spanish origin.
Available evidence indicates that the misreporting mw have occurred only in selected areas with relatively small Spanish-origin populations, such as in some Southern States, but it is not apparent in those areas with the largest concentrations of Spanish-origin persons. For a fuller discussion of the reporting in the Spanish-origin item, see the forthcoming 1980 census Supplementary Report, "Persons of Spanish Origin by State: 1980" (PC80-Sl).

The Spanish-origin question was asked on a l00-percent basis for the first time in 1980. A similar question was asked on the 1970 5-percent sample questionnaire. For 1980, the category "No, not Spanish/Hispanic" appeared first (the corresponding category appeared last in 1970). Also, the terms "Mexican-American" and "Chicano" are added to the term "Mexican." The category "Central or South American," included in 1970, was dropped.

Although a question on Spanish origin was included in 1970, it was not the major identifier used to classify the Hispanic population in the 1970 census as it is in 1980. Depending on the section of the country, 1970 census data for "Persons of Spanish Heritage" were variously defined as "Persons of Puerto Rican Birth or Parentage" (in New York, New Jersey, and Pennsylvania), as "Persons of Spanish language or Spanish Surname" (in Arizona, California, Colorado, New Mexico, and Texas), and as "Persons of Spanish Language" (in the remaining 42 States and the District of Columbia). "Spanish Language" referred to those persons who in 1970 reported Spanish as their mother tongue, as well as persons in families in which the household head or spouse reported Spanish as his or her mother tongue.