The 2000 census allowed people, for the first time, to identify themselves as being of two or more races, and now the 2010 figures (pdf) show people of mixed race are growing in numbers faster than single-race individuals, 32 percent to 9.2 percent.
Beyond raw census numbers in population growth, the jump might signal a growing acceptance of people embracing race and ethnicity.
"There's been more education about what race and ethnicity constitute," explains Matthew Lee, a psychology professor at James Madison University, "so more people are more comfortable in applying the terminology."
In the most recent census, people who categorize themselves as both black and white grew 134 percent. White-Asian is the next-largest mixed-race category, at 87 percent.
"These comparisons show substantial growth in the multiple-race population, providing detailed insights to how this population has grown and diversified over the past decade," said Nicolas Jones, census chief for racial statistics.
Border states and states with large urban centers had the highest density of people of mixed race.
Below is an interactive chart comparing mixed-race figures from 2000 and 2010.