Men and women both generally wear an upper jacket and a saronglike lower garment called a sampot. Almost 4 million people lived in the Khmer Empire at its height from the 11th to the 13th century AD . Conquest by Thai forces in the 14th and 15th centuries reduced the population by about half. Wars during the 17th to the 19th century reduced the Khmer to about 1 million people by the mid-19th century. By 1960, however, the number of Khmer had again increased to almost 5 million, and by 1995 the number of Khmer had reached more than 8 million.
Aboriginal groups occupy the upland area around the borders of Cambodia.
Muslim Chams live in villages in the eastern part of the country. For centuries colonies of southern Chinese have made their homes in Cambodian cities, and some have intermarried with the Khmer. Vietnamese settlers began arriving in southeastern Cambodia in the late 17th century. Thai live along the western fringes of Cambodia, near the border with Thailand. The Khmer are primarily an agricultural people.