Multiracial Americans officially numbered 6.1 million in 2006, or 2.0% of the population. There is considerable evidence that an accurate number would be much higher. Prior to the mid-20th century, many people hid their multiracial heritage. 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. Some are now reclaiming additional ancestries. 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 usually Native American.