 Puerto Rico went from being two-thirds black and mulatto in the beginning of the 19th century, to being nearly 80% white by the middle of the 20th century.This was compounded by more flexible attitudes to race under Spanish rule, as epitomized by the "Regla del Sacar".Under Spanish rule, Puerto Rico had laws such as "Regla del Sacar" or "Gracias al Sacar", which made persons of mixed African-European ancestry to be classified as white, which was the opposite of "one-drop rule" in US society after the American Civil War.