http://www.newgeography.com/content/002799-staying-same-urbanization-america (complete article)
The recent release of the 2010 US census data on urban areas (Note 1) shows that Americans continue to prefer their lower density
lifestyles, with both suburbs and exurbs (Note 2) growing more rapidly than the historic core municipalities. This may appear to be at odds with the recent Census Bureau 2011 metropolitan area population estimates, which were widely mischaracterized as indicating exurban (and suburban) losses and historical core municipality gains. In fact, core counties lost domestic migrants, while suburban and exurban counties gained domestic migrants.