sentences:  By the late 19th century the Afro-Argentine population consisted mainly of women, who mixed with the large numbers of European immigrants.Despite the fact that in the 1960s it was calculated that Argentina owed two thirds of the volume of its population to European immigration, over 5% of Argentines state they have at least one black ancestor, and a further 20% state they do not know whether or not they have any black ancestors.Genetic studies carried out in 2005 showed that the average level of African genetic contribution in the population of Buenos Aires is 2.2%, but that this component is concentrated in 10% of the population who display notably higher levels of African ancestry.