The finding of greatest concern to the authors was that the percentage of Americans volunteering appears to be on the decline. In 2004, the national rate was 29 percent.
"Our failure to retain more volunteers from one year to the next is cause for concern," wrote David Eisner, chief executive officer of the Corporation for National and Community Service, "and should serve as a wake-up call to all those individuals, groups and organizations that care deeply about addressing the nation's most pressing needs."
Among the 10 largest metropolitan areas, Philadelphia ranked fifth, doing quite a bit better than New York and Los Angeles, somewhat worse than Dallas and Chicago.
Nationally, Minneapolis-St. Paul led the rankings, with 40.5 percent of its residents volunteering. Las Vegas was last at 14.4 percent.
The findings are based on answers to a question included each September as part of the Current Population Survey of the U.S. Census Bureau. While the survey, which questions 100,000 Americans, is considered reliable on a national scale, it has a relatively high margin of error as it applies to specific locales.
Researchers found some explanatory trends in the data.
They concluded that volunteerism tends to be higher in places with high rates of home ownership, relatively low population density, short commuting times, low poverty rates, high education levels, and strong community organizations and associations.
Most of the metropolitan areas with the highest ratings in the study were medium-sized places - many of them in the middle of the country - that don't have large numbers of low-income residents. Among the leaders were Salt Lake City; Omaha, Neb.; Austin, Texas; and Portland, Ore.
Contact senior writer Larry Eichel at 215-854-2415 or email@example.com.