Think volunteering only helps others? Think again. People who volunteer at least two hours a week enjoy a number of health benefits, including lower rates of depression and heart disease, studies show. What's more, volunteering gives people a sense of purpose and helps keep them active and connected to others.

Americans volunteered a total of 8.1 billion hours in 2010, according to a new report from Volunteering in America. But that doesn't mean everyone is equally altruistic. Keep clicking to see the cities with the lowest rate of volunteers...

The Motor City kicks off the list of U.S. cities that volunteer the least, with a volunteer rate of 25.6 percent.

Volunteer rate: 25.4 percent

Volunteer rate: 25.4 percent

Volunteer rate: 25.1 percent

Volunteer rate: 25.1 percent

Volunteer rate: 25 percent

Volunteer rate: 24.8 percent

Volunteer rate: 24.5 percent

Volunteer rate: 24.4 percent

Volunteer rate: 24 percent

Volunteer rate: 22.8 percent

Volunteer rate: 22.5 percent

Volunteer rate: 22.3 percent

Volunteer rate: 22.2 percent

Volunteer rate: 21.5 percent

Volunteer rate: 21.4 percent

Volunteer rate: 19.0 percent

Volunteer rate: 17.2 percent

Are the beaches and sunny weather keeping Miami residents from serving their community? Miami scored lowest on the list of big cities, with a volunteer rate of 15.2 percent.