As of the 2012 census, 51.7 per cent of residents were male. The Rwanda Environment Management Authority hypothesised that the high male-to-female ratio was due to a tendency for men to migrate to the city in search of work outside the agricultural sector, while their wives remained in a rural home. The population is young, with 73 per cent of residents being less than 30 years old, and 94 per cent under the age of 50. The city has a higher proportion of 14–35 year olds than the Rwanda average, with 50.3 per cent versus 39.6 per cent nationwide. Children between birth and seventeen years of age have a below-average share of the total, with 39.6 per cent against 47.7 per cent nationally. These differences are attributed by the National Institute of Statistics of Rwanda (NISR) to the migration of working-age Rwandans from rural to urban areas. Similarly, Kigali has a lower level of over-60s, with 2.6 per cent, than the Rwanda average of 4.9 per cent, also likely reflecting the tendency for non-working-age inhabitants to live rurally. In 2014, the proportion of people classified as living in poverty within Kigali was 15 per cent, compared with 37 per cent 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 per cent of the workforce; utilities and financial services with 21 per cent; trade 20 per cent and government 12 per cent.