Mongolia is not entirely homogeneous with respect to ethnicity and religion. Nearly 90% of the population is Mongols, among whom the Khalky-Mongols are the largest subgroup (about 75% of the total). The next largest group is the Kazakhs (5.3%) who live predominantly in the far west. More recently, they have begun migrating in large numbers to the Kazakhstan. There are also other smaller ethnic groups including Tuvins, Uzbeks Uighurs, Russians, Chinese and others. The national language is Mongolian. Mongolian population density is 1.9 people per square kilometers making it one of the most sparsely populated countries in the world.