Black populations dropping in big cities

>>> there is more hard evident tonight that many of america's cities are changing rapidly as a growing number of african- americans are leaving. families look for economic opportunities outside the rust belt , but there are other factor at play here as well. our report from nbc's kristen welker.

>> hi, guys, we're home.

>> reporter: meet the new modern family, the campbells. like many other middle class african- americans , they traded the city for suburbia, seeking a new life for their children.

>> he wanted my girls to be able to have the diversity of different cultures and a better way of living, and have better schools.

>> i think the suburbs represents to a lot of people getting that brass ring .

>> reporter: william frye who crunched the latest census numbers found that over the past decade there's been an exodus of african- americans leaving major cities.

>> you look at the cities that have the highest concentrations of african- americans . more than half of them are showing declines in the populations of those african- americans .

>> reporter: the cities with the sharpest drops, traditional black strong holds including detroit, chicago, oakland, cleveland and atlanta. detroit lost a quarter of its entire population. one resident left every 22 minutes .

>> african- americans have moved out of the city into the suburbs.

>> reporter: blacks are moving from the north to the south, reversing a trend from the early 20th century when hundreds of thousands of blacks were moving in the opposite direction to escape racism and find work. experts say today's south is more welcoming.

>> it's a kind of mainstreaming of a group that had been marginalized for so long in our history.

>> reporter: families like the walkers now call the suburbs of atlanta home. they are recent transplants from ann arbor , michigan.

>> this is like " leave it to beaver " the black version.

>> reporter: the boomers are also finding new roots.

>> some of them are older, and they are in some ways bringing part of the north back to the south.

>> reporter: black families exploring new choices as color lines blend together in an increasingly diverse america. kristen welker, nbc news, los angeles .

>> by the way, there's more information on this story, including the census numbers just out, and what they're telling us. we put it all on our website tonight, nightly.msnbc.com.