The development of binary thinking about race meant that African Americans, a high proportion of whom have also had European ancestry, were classified as black. Many Americans today are multi-racial without knowing it.
According to the Census Bureau, as of 2002, over 75% of all African Americans had multiracial ancestries.
Perhaps the most significant change for Census 2000 was that respondents were given the option to mark one or more races on the questionnaire to indicate their racial identity.
Census 2000 race data are shown for people who reported a race either alone or in combination with one or more other races.
Most Brazilians of all racial groups (except Asian Brazilians and Natives) are to some extent mixed-race according to genetic research.
In many countries of Latin America and the Caribbean, mixed-race people make up the majority of the population.
Other countries where multiracial people make up a sizable portion of the population are the United States, Canada, the United Kingdom, France, Italy, Brazil, the Netherlands, Spain, parts of Africa and Asia, Australia, New Zealand, Mauritius, and Fiji.
There is considerable evidence that an accurate number would be much higher.
Prior to the mid-20th century, many people hid their multiracial heritage.