The majority of the people of Equatorial Guinea are of Bantu origin. The largest ethnic group, the Fang, is indigenous to the mainland, but substantial migration to Bioko Island since the 20th century means the Fang population exceeds that of the earlier Bubi inhabitants. The Fang constitute 80% of the population and comprise around 67 clans. Those in the northern part of Río Muni speak Fang-Ntumu, while those in the south speak Fang-Okah; the two dialects have differences but are mutually intelligible. Dialects of Fang are also spoken in parts of neighboring Cameroon (Bulu) and Gabon. These dialects, while still intelligible, are more distinct. The Bubi, who constitute 15% of the population, are indigenous to Bioko Island. The traditional demarcation line between Fang and 'Beach' (inland) ethnic groups was the village of Niefang (limit of the Fang), east of Bata.