In the last 30 years, the country has become steadily more racially diverse–and so have many American colleges, the National Journal reports. In 1980, more than 80% of the country was white, and whites accounted for about eight in ten students at Harvard, Yale, and Princeton. Today, less than 65% of the country is white, and it’s non-whites who now account for a majority at all three of those institutions. The four graphs below compare national racial composition averages in 1980, 1990, 2000, and 2010 to six elite universities: three top-flight private schools in the northeast — Harvard, Yale, and Princeton — and three top-flight public schools across the country — the University of Michigan, the University of Texas, and the University of California, Berkeley…