The people of Laos are called Laotians. There are officially 68 ethnic groups in Laos. Among the largest are the Kammu, believed to be the original inhabitants of Laos. About 6 percent of all Laotians are Lao-lum, or lowland Lao; they are related to the people of Thailand (see Volume 9). Other groups include the Lao-theung, or slope dwellers, who form about one-third of the population; and the Laosoung, or mountain dwellers, who constitute about one-tenth of the population.