The size of Phuket's population varies considerably depending on the time of year, although the official census shows around 250,000 people registered as Phuket residents. Additionally, the island receives about three million visitors per year and there is a sizable community of seasonal and temporary workers from other parts of Thailand. The ethnic makeup of Phuket is roughly 35 per cent Chinese (14 per cent countrywide) and 35 per cent Muslim (4 per cent countrywide) and the Chao Nam, or sea gypsies. The Chinese population of Phuket originates from the Hokkien region of China. The Chinese arrived to work the tin mines, but as elsewhere in Asia, they made the transition from providing cheap labour to being merchants. They married native Thais and assimilated into Thai culture. Today the descendants of the early Chinese settlers are responsible for much of the trade and commerce on Phuket. Indonesian-Malayan culture is quite apparent in southern Thailand. Concentrated mostly around Surin and a few other big villages, they work as rice and rubber farmers. In Phuket, muslims of Malaysian extraction came largely to work on the rubber plantations. The Chao Nam or Sea Gypsies are traditionally a nomadic people and there are three Sea Gypsy villages in Phuket. Little is known of their history and traditions as their language is not written. They follow their own animistic religion and are generally darker skinned and heavier with curly black hair. Sea Gypsies are said to have originated in the Andaman and Nicobar Islands between India and Burma.