The people of Pakistan are ethnically diverse. They trace their ethnic lineages to many different origins, largely because the country lies in an area that was invaded repeatedly during its long history. Migrations of Muslims from India since 1947 and refugees from Afghanistan since the 1980s have significantly changed the demographics of certain areas of the country. The people of Pakistan come from ethnic stocks such as Dravidian, Indo-Aryan, Greek, Scythian, Hun, Arab, Mongol, Persian, and Afghan. Although an overwhelming majority of the people is Muslim, religion does not supercede ethnic affiliations. The people follow many different cultural traditions and speak many different languages and dialects. Pakistan has one of the world's most rapidly growing populations. Its people are a mixture of many ethnic groups, a result of the occupation of the region by groups passing through on their way to India. The Pakhtuns of the northwest are a large, indigenous group that has long resisted advances by invaders and that has at times sought to establish an autonomous state within Pakistan. Balochis, who live mainly in the southwest, have also pressed for the creation of a state that would incorporate parts of Afghanistan and Iran. Punjabis reside mainly in the northeast and Sindhis in the southeast. Pakistan is an overwhelmingly (about 97%) Muslim country. Urdu is the official language, but Punjabi, Sindhi, Pashto and Balochi are also spoken; English is common among the upper classes and in the government. Pakistan has a population of 165,803,560 (2006 estimate), yielding an average population density of 213 persons per sq km (551 per sq mi). The country’s population was increasing in 2006 at a rate of 2.1 percent a year. Only 34 percent of the people live in urban areas.