half of Venezuela's land area lies south of the Orinoco, only 5% of Venezuelans live there. The largest and most important city south of the Orinoco is Ciudad Guayana, which is the sixth most populous conurbation. Other major cities include Barquisimeto, Valencia, Maracay, Maracaibo, Barcelona-Puerto La Cruz, Mérida and San Cristóbal. According to a 2014 study by sociologists of the Central University of Venezuela, over 1.5 million Venezuelans, or about 4% to 6% of the country's population, have left Venezuela since 1999 following the Bolivarian Revolution. Ethnicity The people of Venezuela come from a variety of ancestries. It is estimated that the majority of the population is of pardo, or mixed, ethnic ancestry. Nevertheless, in the 2011 census, which Venezuelans were asked to identify themselves according to their customs and ancestry, the term pardo was excluded from the answers. The majority claimed to be moreno or white—51.6% and 43.6%, respectively. Practically half of the population claimed to be moreno, a term used throughout Ibero-America that in this case means "dark-skinned" or "brown-skinned", as opposed to having a lighter skin (this term connotes skin color or tone, rather than facial features or descent). Ethnic minorities in Venezuela consist of groups that descend mainly from African or indigenous peoples; 2.8% identified themselves as "black" and 0.7% as afrodescendiente (Afro-descendant), 2.6% claimed to belong to indigenous peoples, and 1.2% answered "other races". Among indigenous people, 58% were Wayúu, 7% Warao, 5% Kariña, 4% Pemón, 3% Piaroa, 3% Jivi, 3% Añu, 3% Cumanágoto, 2% Yukpa, 2% Chaima and 1% Yanomami; the remaining 9% consisted of other indigenous nations. According to an autosomal DNA genetic study conducted in 2008 by the University of Brasília (UNB), the composition of Venezuela's population is 60.60% of European contribution, 23% of indigenous contribution, and 16.30% of African contribution. During the colonial period and until after the Second World War, many of the European immigrants to Venezuela came from the Canary Islands and Spain with a relevant amount of Galicians and Asturians. These immigrants from Spain had a significant cultural impact on the cuisine and customs of Venezuela. These influences on Venezuela have led to the nation being called the 8th island of the Canaries. With the start of oil exploitation in the early 20th century, companies from the United States began establishing operations in Venezuela, bringing with them U.S. citizens. Later, during and after the war, new waves of