A growing number of people identify with more than one race in the U.S., which is becoming more racially diverse in general, according to new data from the U.S. Census Bureau.

The white population remains the largest racial or ethic group in the country, at 57.8% of the population. But that group has decreased from 63.7% in the last decade, while the multiracial population has increased from 9 million people to 33.8 million in the last 10 years – a 276% increase.

But some states are far less racially diverse than others, falling well below the national average of 61.1%, according to the Census Bureau’s diversity index, which indicates the likelihood that two people within a population chosen at random will be from different race and ethnic groups. Using the index, the Census Bureau determined which states are the most and least racially diverse.

These are the least racially diverse states in the U.S., along with their three largest racial groups: