Ecuadorians (ecuatorianos) are people identified with the South American country of Ecuador. This connection may be residential, legal, historical or cultural. For most Ecuadorians, several (or all) of these connections exist and are collectively the source of their being Ecuadorian. Numerous indigenous cultures inhabited what is now Ecuadorian territory for several millennia before the expansion of the Inca Empire in the fifteenth century. The Las Vegas culture of coastal Ecuador is one of the oldest cultures in the Americas. The Valdivia culture is another well-known early Ecuadorian culture. Spaniards arrived in the sixteenth century, as did sub-Saharan Africans who were enslaved and transported across the Atlantic by Spaniards and other Europeans. The modern Ecuadorian population is principally descended from these three ancestral groups. As of 2010, 77.4% of the population identified as "Mestizos", a mix of Spanish and Indigenous American ancestry, up from 71.9% in 2000. The percentage of the population which identifies as "white" has fallen from 10.5% in 2000 to 6.1% in 2010. Amerindians account for approximately 7.0% of the population and 7.2% of the population consists of Afro-Ecuadorians. Other statistics put the Mestizo population at 55% to 65% and the indigenous population at 25%. Genetic research indicates that the ancestry of Ecuadorian Mestizos is predominantly Indigenous. There are five major ethnic groups in Ecuador: Mestizo, European, Afroecuadorian, Amerindian, and Montubio. Mestizos constitute more than 70% of the population. Ecuador's population descends from Spanish immigrants and South American Amerindians, admixed with descendants of black slaves who arrived to work on coastal plantations in the sixteenth century. The mix of these groups is described as Mestizo or Cholo. Censuses do not record ethnic affiliation, which in any event remains fluid; thus, estimates of the numbers of each group should be taken only as approximations.