The 1990 Census of Population and Housing, which is the 21st decennial enumeration of the United States, also marks the bicentennial of Federal census taking in this country. The inquiries stretching over the years since 1790 reflect the Nation's changing interests and data needs, as well as its people, government, and economy. Emphasis has moved from basic head counts to concern about data on housing, employment, income, transportation, ethnicity, education, and migration that can be used for planning and funding at all levels of society, from the neighborhood to the country as a whole.