A new U.S. 2012 policy brief has revealed that increasing racial and ethnic diversity has long been apparent at the national level and in our nation's largest metropolitan gateways. 

Researchers found that since 1980 over nine-tenths of all cities, suburbs and small towns have become more diverse and rural communities are following the lead of their urban counterparts. 

Researchers found that only one-third of white-dominant places now exist, down from two-thirds 30 years ago. There are now a growing number of communities where minorities are a significant share of the population and often where no group is a majority.

Despite the general upward trend in diversity, dramatic contrasts are still apparent between communities. 

At the high end of the diversity scale, places such as Oakland and Jersey City now have roughly equal proportions of white, black, Hispanic and Asian residents. At the low end, the most homogeneous communities tend to remain all white or all Hispanic.

A unique feature of this study is that it included micropolitan areas where the largest community has a population under 50,000, as well as rural areas.

Researchers said that studying these areas is important because they form the core of small-town America and even small towns now have to adapt to newcomers who are from different backgrounds than their longtime residents.