Over the last six decades, America has rapidly become a multi-ethnic, multiracial, and multicultural country.

We take this for granted today, forgetting it was not always true. At the time of the American Revolution, America’s free population was not just overwhelmingly white, but overwhelmingly of British origin. Somewhat less than 2 percent were free African Americans (very few of whom could vote) and Native Americans (who were not taxed and were only counted in the first census if they were living as part of a white political community, and few were). Other groups were so small as to scarcely even be measurable.

According to one estimate, of the population of Americans on the eve of the Revolution, almost 170 years after the first European settlements in what is now the United States, an estimated 85 percent were of British origin. America’s initial political community was not simply white but, in its basic demographics, remarkably homogenous.

Over the next two centuries, American demographics went through various permutations and combinations of settlement and immigration. In 1970, the year of the first census following the 1965 Hart-Celler immigration law—which led to a rapid change in America’s demographics—America was 83 percent white non-Hispanic and 11 percent African American. Of the 4.5 percent estimated Hispanic population that made up most of those not captured in the first two groups, 80 percent were native born (as opposed to about 60 percent today).