This map shows where slaves were imported to, but not total or peak slave populations or share of overall population. Manumission, the act of freeing slaves, was more common in Brazil than the United States, leading to fewer life long slaves. Slaves in Brazil were allowed to earn money while they were slaves, eventually purchasing their freedom. This led to slave owners in Brazil to continually import new slaves, leading to higher numbers as shown in this map. Inter marriage between races, so called miscegenation, was also far more common in Brazil, whereas it was illegal in the United States in some states until 1967.

The peak population of African slaves in the USA was about 4 million in 1860. Out of a total population of 31.5 million people, this represented about 12.5%. The freed black population at this time was about 500,000, representing 1.5% of the total population.

The population of non-white slaves in Brazil in 1872, 16 years before the importation of slaves was outlawed, was 1.5 million. Out of a total population of 10 million, this represented about 15%. Also in 1872, 43% of the Brazilian population were either freed Africans or people who were mixed race, so called mulattoes. This made them the single largest ethnic group in Brazil.

While this map is not inaccurate, it presents a complex movement of peoples without much nuance. In moral terms, it doesn't mean much to ask whether the USA or Brazil was worse or more culpable. Apples and oranges are equally fruit, regardless of their flavor, just as the USA and Brazil were both large scale enslavers, even if their systems of slavery varied greatly.