Niger ( or ; ), officially the Republic of Niger, is a landlocked country in Western Africa, named after the Niger River. Niger covers a land area of almost 1,270,000 km2, making it the largest nation in West Africa, with over 80 percent of its land area covered by the Sahara desert. The country’s predominantly Islamic population of 17,138,707 is mostly clustered in the far south and west of the nation. The capital city is Niamey, located in the far-southwest corner of Niger. Niger is a developing country, and is consistently one of the lowest-ranked in the United Nations’ Human Development Index (HDI); it was ranked last at 187th for 2013. Much of the non-desert portions of the country are threatened by periodic drought and desertification. The economy is concentrated around subsistence and some export agriculture clustered in the more fertile south, and the export of raw materials, especially uranium ore. Niger faces serious challenges to development due to its landlocked position, desert terrain, poor education and poverty of its people, lack of infrastructure, poor health care, and environmental degradation. Nigerien society reflects a diversity drawn from the long independent histories of its several ethnic groups and regions and their relatively short period living in a single state. Historically, what is now Niger has been on the fringes of several large states. Since independence, Nigeriens have lived under five constitutions and three periods of military rule. Following a military coup in 2010, Niger has become a democratic, multi-party state. A majority live in rural areas, and have little access to advanced education.