There is a wide variety of housing options in Nairobi. The options range from privately owned housing units/apartments, rented units, leased spaces and even houses on mortgage. Most wealthy Kenyans live in Nairobi, but the majority of Nairobians are of average and low income. Half of the population has been estimated to live in slums which cover just 5% of the city area. The growth of these slums is a result of urbanisation, poor town planning, and the unavailability of loans for low income earners.