A U.S. Census Bureau report released today shows that in many of the largest cities of the most-populous metro areas, downtown is becoming a place not only to work but also to live. Between the 2000 and 2010 censuses, metro areas with 5 million or more people experienced double-digit population growth rates within their downtown areas (within a two-mile radius of their largest city's city hall), more than double the rate of these areas overall.

Chicago experienced the largest numeric gain in its downtown area, with a net increase of 48,000 residents over 10 years. New York, Philadelphia, Salt Lake City and Washington also posted large population increases close to city hall. These downtown gains were not universal, however: New Orleans and Baltimore experienced the greatest population declines in their downtown areas (35,000 and slightly more than 10,000, respectively). Two smaller areas in Ohio - Dayton and Toledo - also saw downtown declines of more than 10,000.

These are just some of the findings in the new 2010 Census special report, Patterns of Metropolitan and Micropolitan Population Change: 2000 to 2010. The report uses 2010 Census results to examine contemporary geographic patterns (as well as changes since the 2000 Census) of population density and distribution by race, Hispanic origin, age and sex for metro and micro areas collectively as well as individually. Metro areas contain at least one urbanized area of 50,000 population or more, while micro areas contain at least one urban cluster of less than 50,000, but at least 10,000.

"By including totals for both 2000 and 2010, this report helps us to understand patterns of change for this past decade," Census Bureau Deputy Director Nancy Potok said. "The report, together with its associated online maps, graphics and statistical tables, provides a detailed view of the nation's centers of population and economic activity."

A common theme for the non-Hispanic white alone population from 2000 to 2010 was population increases in the central areas of many of the largest principal cities, especially those in the largest metro areas.

"The Washington metro area is a notable example of this pattern," said Steven Wilson, a co-author of the report. "We see increases in the non-Hispanic white population, in both numeric terms and share of the total population, in many of the District's census tracts in or close to the city's downtown area."

At the same time, this group's share of the population declined by 10 or more percentage points in many tracts in the surrounding suburbs of Washington, D.C.

These demographic patterns were not uniform across all race and ethnic groups; the black alone population increased in most metro areas outside the area's largest city. In Atlanta, for example, this group's share of the population rose by at least 10 percentage points in wide swaths surrounding the city. For Hispanics, growth was greatest in pockets along principal city perimeters and adjacent territory.

In several sections of the report, census tract data were examined to provide a neighborhood-level perspective on demographic patterns within individual metro areas. Because census tracts often change boundaries from one census to the next, one of the report's innovations was to retabulate 2000 Census data in updated 2010 Census tracts, thereby allowing the calculation of 2000 to 2010 change data by tract. Another feature of the report is the construction of distance bands as measured from city hall. This permits a look at population distribution and density at various distance ranges from a metro area's largest city center.

Along with metro and micro area data for all variables in the report, two online data tools were released: a series of interactive population pyramids showing the age and sex structure of all metro and micro areas in 2000 and 2010, and a set of "distance profiles" of the population for all metro areas. Also, an interactive mapping tool that allows users to see metro and micro area and census tract-level data is now available.

Other highlights:

• More than one in 10 U.S. residents lived in either the New York or Los Angeles metro area in 2010.
• Although metro areas covered only slightly more than one-quarter of the nation's land area, they were home to eight of every 10 people.
• The Hispanic share of the population increased in every U.S. metro area.
• While the non-Hispanic white alone, black alone and Asian alone populations grew faster in metro areas than in micro areas, the reverse was true for Hispanics.
• Next to those who were non-Hispanic white alone, Hispanics were the most populous race or ethnic group in most metro and micro areas in the western half of the U.S., with single-race blacks the largest in most areas in the eastern half.
• Metro area populations were younger (a median of 36.6 years) than the population in either micro areas (39.3 years) or territory outside either of these areas (41.9 years).
• Areas with the highest median ages were either in slow-growing regions like western Pennsylvania, which had past outmigration of the young combined with "aging in place," or were faster-growing areas in parts ofFlorida and Arizona that were traditional retiree migration destinations.
• Areas with the lowest median ages included metro areas and micro areas in Utah, southern Idaho and along the U.S.-Mexican border.