TSh 19.5 trillion, a 15 per cent increase over 2012. Transport Most transport in Tanzania is by road, with road transport constituting over 75 per cent of the country's freight traffic and 80 per cent of its passenger traffic. The road system is in generally poor condition. Tanzania has two railway companies: TAZARA, which provides service between Dar es Salaam and Kapiri Mposhi (in a copper-mining district in Zambia), and Tanzania Railways Limited, which connects Dar es Salaam with central and northern Tanzania. Rail travel in Tanzania often entails slow journeys with frequent cancellations or delays, and the railways have a deficient safety record. In Dar es Salaam, there is a huge project of rapid buses, Dar Rapid Transit (DART) which connects suburbs of Dar es Salaam city. The development of the DART system consists of six phases and is funded by the African Development Bank, the World Bank and the Government of Tanzania. The first phase began in April 2012, and it was completed in December 2015 and launched operations in May 2016. Tanzania has four international airports, along with over 120 small airports or landing strips. Airport infrastructure tends to be in poor condition. Airlines in Tanzania include Air Tanzania, Precision Air, Fastjet, Coastal Aviation, and ZanAir. Communications In 2013, the communications sector was the fastest growing in Tanzania, expanding 22.8 per cent; however, the sector accounted for only 2.4 per cent of gross domestic product that year. As of 2011, Tanzania had 56 mobile telephone subscribers per 100 inhabitants, a rate slightly above the sub-Saharan average. Very few Tanzanians have fixed-line telephones. Approximately 12 per cent of Tanzanians used the internet , though this number is growing rapidly. The country has a fibre-optic cable network that replaced unreliable satellite service, but internet bandwidth remains very low. Water supply and sanitation Water supply and sanitation in Tanzania has been characterised by decreasing access to improved water sources in the 2000s (especially in urban areas), steady access to some form of sanitation (around 93 per cent since the 1990s), intermittent water supplies, and generally low quality of service. Many utilities are barely able to cover their operation and maintenance costs through revenues because of low tariffs and poor efficiency. There are significant regional differences, with the best performing utilities being Arusha, Moshi, and Tanga. The government of Tanzania has embarked on a major sector reform process since 2002. An