United States censuses have obtained information on race for each individual counted since the first decennial census in 1790. But for the first time, in Census 2000, respondents were asked to report one or more races that they considered themselves or other members of their household to be.

The people who responded to the question on race by ticking only one race were clubbed under the “race alone” population, while those who reported more than one were referred to as “in combination” population.

For example, of the total U.S. population of 281.4 million people, 3.6 percent reported only Asian, while an additional 1.7 million reported Asian in combination with one other race. Within this category, the most common combinations were “Asian and white” (52 percent), followed by “Asian and some other race” (15 percent).

The Census Bureau says that because of these changes, the Census 2000 data is not directly comparable with data from the 1990 census or earlier censuses.

The 1990 census counted 6.9 million Asians. Using the Asian-alone group in 2000, this population is seen to increase by 3.3 million, or 48 percent, between 1990 and 2000. But if the “Asian-alone or in combination” population is used, the increase is five million, or 72 percent. The bureau says it would be correct to say the range of increase in the Asian population was 48-72 percent.

There has been some comment on how this multiplicity of identities would impact voting rights and federal programs, but those who support the change say it is an acknowledgement of the growing number of multiracial Americans and would help to legitimize their multiracial identities.