In the northeastern areas of Lahu settlement in Yunnan, Lahu villages resemble those of their Han and Yi neighbors. Based on irrigated-rice production, such villages are permanent settlements, some numbering over 200 households and more than 1,000 people. Houses are substantial earthen structures in the Chinese style, with roofs of tiatch or wooden boards. Further southwest in Yunnan, and hrough Myanmar's Shan State, north Thailand, and northwestern Laos, Lahu villages tend to be much smaller and thus better suited to a predominantly swidden-farming economy. They are also less permanent, being relocated every eight to ten years. Thirty houses and 120 people are about normal, but the range is considerable. Houses are usually of bamboo, raised on wooden or thick bamboo piles and thatched with leaves or cogon grass. Averaging about 3 by 3.5 meters, they vary in size according to the number of occupants rather than family wealth. In some of the southwestern settlement areas in Yunnan, at least until the 1950s, longhouses (up to 15 meters in length) were not uncommon for extended families of 40 to 100 people, each nuclear family unit having its own apartment and cooking hearth. The settlements of the Kucong (Co Sung) reflect their hunting-and-gathering economy. These people make temporary huts, or even simpler wind shelters, by covering a bamboo or wooden frame with wild banana or bamboo leaves. They sleep on leaves next to their house fires. Such huts have to be rebuilt about once a month.