However, the 2000 census included a racial self-identification question in Puerto Rico and, for the first time in since 1950, allowed respondents to choose more than one racial category to indicate mixed ancestry. (Only 4.2% chose two or more races.) With few variations, the census of Puerto Rico used the same questionnaire as in the U.S. mainland. According to census reports, most islanders responded to the new federally mandated categories on race and ethnicity by declaring themselves "white"; few declared themselves to be black or some other race. However, it was estimated 20% of white Puerto Ricans may have black ancestry.