Iowa: 3.1%. According to our research of Iowa and other state lists there were 2 registered sex offenders living in Aurora, Iowa as of September 06, 2015. The ratio of number of residents in Aurora to the number of sex offenders is 86 to 1.
William G. Sumner, who coined the term ethnocentrism, is famously known as America's first sociology professor. He taught social sciences at the Yale University. It is wondrous, really, how this world is made up of so many different people belonging to different races or ethnicities.
This theme was taken up by historian James Belich in his Dominion Day address in Wellington New Zealnad in September 2007. There are psychological aspects of the association of ethnocentrism with conflict, such as 'otherizing' but also deeper effects linked to trauma and memory. I could write much, much more. See the work of Gail Weldon (her South Africa PhD) on Rwanda and South Africa.