Vietnam is shaped like an elongated 'S' and stretches the length of the Indochinese Peninsula, bordering the China Sea in the east. It encompasses a vast sea area including a string of thousands of archipelagoes stretching from the Tonkin Gulf to the Gulf of Thailand. Vietnam has three principal regions, with the central region flanked by two rice-producing areas supplied by the rich alluvial deltas of the Red River in the north and the Mekong in the south. Vietnam is basically an agricultural country and over 80 percent of the population live in rural areas supported by agriculture, forestry and fishing. The principal crops are rice, sugar cane, fruit and vegetables, sweet potatoes and cassava. Vietnam became a member of the World Trade Organization (WTO) in 2007, and it is believed that the country as a whole will benefit economically. Vietnamese is a mixture of Austro-Asiatic languages, sharing many similarities with the Mon-Khmer, Thai and Muong languages.