The U.S. became more racially and ethnically diverse from 2010 to 2020, according to the U.S. Census Bureau. But despite the nation's overall increase in diversity, not all states saw the same amount of change.
To measure racial and ethnic diversity, the census relies on a Diversity Index score. The index measures the probability – between 0 and 1, translated as a percentage – that two people chosen randomly will be from different races and ethnicities. Numbers close to 100% mean that nearly everyone in a population has different racial and ethnic characteristics.
From 2010 to 2020, the nation's average Diversity Index score increased by 6 percentage points, from 55% to 61%. Individual states saw their racial and ethnic diversity increase anywhere from 0.9 to 12 percentage points over the same time period.
North Dakota saw the most increase in diversity, growing by 12 percentage points over the decade. Massachusetts and Washington followed, with an increase of 11.2 and 10.5 percentage points, respectively. A total of 34 states saw more of an increase in diversity than the national average.
North Dakota's increase in diversity was fueled by its decreasing white population. As of 2020, 82% of residents identified as "white alone," down from 89% in 2010.
North Dakota's non-white population saw less dramatic change. The American Indian and Alaska Native population – North Dakota's second-largest demographic group – decreased by just 1 percentage point from 2010, making up 5% of the state population in 2020. Meanwhile, the population that identified as Hispanic or Latino grew by 2 percentage points in 2020 and now makes up 4% of the total population.
While 17 states had less of an increase in diversity than the national average, many of these states were already racially diverse to begin with.
Hawaii is the only state that saw its Diversity Index increase by less than 1 percentage point from 2010 to 2020. Despite being the state that saw the least amount of increase in diversity according to 2020 data, Hawaii has maintained its ranking as the most diverse state in the country for the last 10 years.
After Hawaii, California and Nevada are the most racially and ethnically diverse states in the U.S. Vermont, West Virginia and Maine have the least racial diversity in the country.
On average, the U.S. saw a 6.2 percentage point increase in diversity between 2010 and 2020. This change was driven by a decrease in the country's white population, but also by an increase in those identifying with other racial or ethnic groups.
While whites remain the most prevalent racial group in the U.S., they make up a smaller portion of the population than they once did. In 2010, the number of Americans identifying as "white only" made up 64% of the population, but by 2020 that number had fallen to 58%.
In some states, whites are no longer the most prevalent group. Census data for 2020 shows that in California and New Mexico, those identifying as Hispanic or Latino became the largest group; in Hawaii, most people identify as Asian; and in Washington, D.C., most identify as Black or African American.
The Hispanic or Latino population is the country's second-largest ethnic or racial group, making up almost 19% of the total population. According to USAFacts, the Hispanic population grew 23% from 2010 to 2020. This growth was also seen at the state level.
According to USAFacts, 44% of Hispanics in the U.S. reside in California or Texas.