This article is about the demographic features of the population of Vietnam, including population density, ethnicity, education level, health of the populace, economic status, religious affiliations and other aspects of the population. Originating in northern Vietnam, the Vietnamese people pushed southward over two millennia to occupy the entire eastern seacoast of the Indochinese Peninsula. Ethnic Vietnamese, or Viet (known officially as Kinh), live in the lowlands and speak the Vietnamese language, as opposed to the many ethnic groups of Vietnam who are known to occupy the mountainous regions. The Kinh group does represent much of the cultural and political landscape of Vietnam. Population Historic estimates UN estimates Population pyramids Source: Vital statistics UN estimates of births and deaths Birth, death and fertility rates The total fertility rate of Vietnam has been influenced by the government's family planning policy, the two-child policy. Source: General Statistics Office of Vietnam. Fertility rate by region and province Source: General Statistics Office of Vietnam. Ethnic groups The Vietnamese government recognizes 54 ethnic groups, of which the Viet (Kinh) is the largest; according to official Vietnamese figures (2019 census), ethnic Vietnamese account for 85.32% of the nation's population and the non-Vietnamese ethnic groups account for the remaining percent. The ethnic Vietnamese inhabit a little less than half of Vietnam, while the ethnic minorities inhabit the majority of Vietnam's land (albeit the least fertile parts of the country). The relation between China and Vietnam also declined following reunification in 1975, with Vietnam siding with the Soviet Union against China in the Chinese-Soviet split. Tensions peaked when Vietnam and Cambodia started a war, Cambodia lead by Pol Pot being a Chinese ally, resulting in a Chinese invasion of Vietnam in 1979. In 1978-79, some 450,000 ethnic Chinese left Vietnam by boat as refugees (many officially encouraged and assisted) or were expelled across the land border with China. In recent years the government has performed an about turn and is encouraging overseas Hoa to return and invest, but the ethnic Chinese population has been in continuous decline since the 1970s due to assimilation and low birth rates. The central highland peoples commonly termed Degar or Montagnards (mountain people) comprise two main ethnolinguistic groups--Malayo-Polynesian and Mon–Khmer. About 30 groups of various cultures and dialects are spread over the highland territory. Other minority groups include the Cham—remnants of the once-mighty Champa Kingdom, conquered by the Vietnamese in the 15th century, Hmong,