Another study (covering all regions of Brazil in a sample of 200 people of different colors) found out that the average Brazilian would be about 80% European in all regions except in the South where they would be, on average, about 90% European (regardless of census classification).
The ancestry is quite irrelevant for racial classifications in Brazil. A genetic resource conducted by UFMG on self-identified White Brazilians found that, on the paternal side, 2.5% of them had an African lineage and none of them revealed Amerindian ancestry. On the maternal side, 33% had an Amerindian lineage and 28% African. This finding reflected the centuries of miscegenation between Portuguese males and African or Amerindian females, given that few female Portuguese immigrants arrived during Brazil’s colonization. A survey in Rio de Janeiro also concluded that “racial-purity” is not important for a person to be classified as White in Brazil. The survey asked respondents if they had any ancestors who were European, African or Amerindian. As much as 52% of the Whites from Rio reported they have some non-European ancestry, with 38% reporting to have some Black African ancestry (25% of Whites reported to be of African and European ancestry, while another 15% reported to be of African, Amerindian and European ancestry). Moreover, 14% of the Whites reported to be of Amerindian and European ancestry. In consequence, only 48% of the Whites from Rio claimed to be of strictly European ancestry. Then in Brazil to have African or Amerindian ancestry and identify as White is not inconsistence, neither is it a problem for them to admit to having non-White ancestors (even though the “whitening ideology” may lead them to downplay these ancestors and the stigma associated with being Indian or African may have prevented more people from reporting non-White ancestors). The survey also found that only 25% of Black Brazilians claimed strictly African ancestry, with a larger segment of both Blacks and Browns, 35% and 36% respectively, claiming to be of African, Amerindian and European ancestries.
The conception of Whiteness in Brazil is based on the skin color of a person, which contrasts with the conception of race and ancestry, as used in the United States. According to the 1991 Census, 55% of the children whose mother was White and father was Brown were classified as Whites. Another 6% of children born to both Brown parents were classified as Whites and 2% of children born to a Black-Black couple were also identified as Whites. This analysis shows that the ancestry of a person is quite insignificant to racially classify people in Brazil.
http://en.wikipedia.org/wiki/White_Brazilian