The People it is reckoned that Laos has somewhere between 70 to over 100 ethnic groups (no one can be sure!), and these are divided into four major cultural-linguistic collections. Hill tribes make up a significant proportion of the population, though precisely how many ethnic groups actually exist in Laos remains uncertain; figures range from a government list of 68 to estimates by independent ethnographers of 120 or more. Laos' rich and complex linguistic mixture is such that, in extreme cases, some minorities consist of only a few hundred people, and only occupy a particular mountaintop or valley! The Lao-Loom, or lowland Lao, speak Laotian Tai and live in the lowlands and cities and along the Mekong River. The Lao-Loom comprise about two-thirds of the country's total population.