Kigali young, with 73 percent of residents being less than 30 years old, and 94 percent under the age of 50. In 2014, the proportion of people classified as living in poverty within Kigali was 15 percent, compared with 37 percent for Rwanda as a whole. The 2012 census recorded a workforce of 487,000 in Kigali. The city's biggest employment sector is agriculture, fishing and forestry, covering 24 percent of the workforce; utilities and financial services with 21 percent; trade 20 percent and government 12 percent. Mines for tin ore (cassiterite) have operated nearby, and the city built a smelting plant
Kigali three administrative districts—Nyarugenge, which lies in the south west, Kicukiro in the south east, and Gasabo, which occupies the northern half of the city's territory. Kigali lies in a region of rolling hills, with a series of valleys and ridges joined by steep slopes. Kigali lies between the two mountains of Mount Kigali and Mount Jali, both of which have altitudes over , while the lowest areas of the city have an altitude of . Geologically, the city lies in a granitic and metasedimentary region, with lateritic soils on the hills and alluvial soils in the valleys. The Nyabarongo River,