Miami has the highest percentage of foreign-born residents in the US—60.6 percent in 2003, and that figure has likely increased in the intervening time. As sociologist Robert Putnam reminds us, diversity decreases trust and reduces social capital, including volunteering.

Blame it on the traffic. Or the number of new immigrants. Or the allure of the beach. Whatever the reason, Miami has secured the bottom spot - No. 50 among major U.S. cities - in new rankings of the percentage of adults who volunteer. Nationally, the volunteer rate fell in 2007 for the second year in a row, to 26.2 percent, according to the Corporation for National and Community Service, which is releasing its report Sunday. It showed Miami with a volunteerism rate of 14.5 percent, replacing Las Vegas in last place among major metropolitan areas.

To be fair, the study found 620,000 volunteers were recruited in Miami last year, more than 60,000 over the previous year. And many local nonprofits say they have more volunteers than ever. But there's no denying how far Miami lags behind other cities, particularly No. 1 Minneapolis-St. Paul, with a 39.3 percent rate. [Miami ranks last in volunteering, (AP), July 27, 2008]