This includes the income of the householder and all other individuals 15 years old and over in the household, whether they are related to the householder or not. Because many households consist of only one person, average household income is usually less than average family income. Although the household income statistics cover calendar year 1999, the characteristics of individuals and the composition of households refer to the time of enumeration (April 1, 2000). Thus, the income of the household does not include amounts received by individuals who were members of the household during all or part of calendar year 1999 if these individuals no longer resided in the household at the time of enumeration. Similarly, income amounts reported by individuals who did not reside in the household during 1999 but who were members of the household at the time of enumeration are included. However, the composition of most households was the same during 1999 as at the time of enumeration.

Gross rent as a percentage of household income in 1999 is a computed ratio of monthly gross rent to monthly household income (total household income in 1999 divided by 12). The ratio is computed separately for each unit and is rounded to the nearest tenth. Units for which no cash rent is paid and units occupied by households that reported no income or a net loss in 1999 comprise the category "Not computed."