population Laos has no less than 68 tribal groups. About half of the population in Laos are Lao Loum, "lowland Lao" who live in the river plains and mostly along the Mekong region. Officially, this group includes the Lao Tai, who are subdivided into numerous subgroups. The Lao Theung (20-30%), or "upland Lao", live on mid-altitude slopes (officially defined as 300-900m), and are by far the poorest group, formerly used as slave labor by the Lao Loum. The label Lao Sung (10-30%) covers mostly Hmong and Mien tribes who live higher up in the mountains and which have been moving into Laos due to suppression in China about 200 years ago. Due to the lack of land and the warmer climate, the Lao Sung (e.g. Hmong) have been living in rougher mountain areas since than. They are also very known in the neighboring countries as well. There are also an estimated 2-5% Chinese and Vietnamese, concentrated in the cities living in Laos. And its getting more, expecially Chinese people who come to invest and do trade or transfer forest into plantations!