African countries. Access to sanitation remains low; the United Nations estimates that in 2006, 34% of urban and 20% of rural dwellers had access to improved sanitation. Kigali is one of the cleanest cities in Africa. Government policy measures to improve sanitation are limited, focusing only on urban areas. The majority of the population, both urban and rural, use public shared pit latrines. Rwanda's electricity supply was, until the early 2000s, generated almost entirely from hydroelectric sources; power stations on Lakes Burera and Ruhondo provided 90% of the country's electricity. A combination of below average rainfall and human activity, including the draining of the Rugezi wetlands for cultivation and grazing, caused the two lakes' water levels to fall from 1990 onwards; by 2004 levels were reduced by 50%, leading to a sharp drop in output from the power stations. This, coupled with increased demand as the economy grew, precipitated a shortfall in 2004 and widespread loadshedding. As an emergency measure, the government installed diesel generators north of Kigali; by 2006 these were providing 56% of the country's electricity, but were very costly. The government enacted a number of measures to alleviate this problem, including rehabilitating the Rugezi wetlands, which supply water to Burera and Ruhondo and investing in a scheme to extract methane gas from Lake Kivu, expected in its first phase to increase the country's power generation by 40%. Only 18% of the population had access to electricity in 2012, though this had risen from 10.8% in 2009. The government's Economic Development and Poverty Reduction Strategy for 2013–18 aims to increase access to electricity to 70% of households by 2017. The government has increased investment in the transport infrastructure of Rwanda since the 1994 genocide, with aid from the United States, European Union, Japan, and others. The transport system consists primarily of the road network, with paved roads between Kigali and most other major cities and towns in the country. Rwanda is linked by road to other countries in the East African Community, namely Uganda, Tanzania, Burundi and Kenya, as well as to the eastern Congolese cities of Goma and Bukavu; the country's most important trade route is the road to the port of Mombasa via Kampala and Nairobi, which is known as the Northern Corridor. The principal form of public transport in the country is the minibus, accounting for more than half of all passenger carrying capacity. Some