is still behind neighbouring countries. Currency Burundi's currency is the Burundian franc (ISO 4217 code BIF). It is nominally subdivided into 100 centimes, though coins have never been issued in centimes in independent Burundi; centime coins were circulated only when Burundi used the Belgian Congo franc. Monetary policy is controlled by the central bank, Bank of the Republic of Burundi. Transport Burundi's transport network is limited and underdeveloped. According to a 2012 DHL Global Connectedness Index, Burundi is the least globalised of 140 surveyed countries. Bujumbura International Airport is the only airport with a paved runway and as of May 2017 it was serviced by four airlines (Brussels Airlines, Ethiopian Airlines, Kenya Airways and RwandAir). Kigali is the city with the most daily flight connections to Bujumbura. The country has a road network but less than 10% of the country's roads were paved and private bus companies were the main operators of buses on the international route to Kigali; however, there were no bus connections to the other neighbouring countries (Tanzania and the Democratic Republic of Congo). Bujumbura is connected by a passenger and cargo ferry (the MV Mwongozo) to Kigoma in Tanzania. There is a long-term plan to link the country via rail to Kigali and then onward to Kampala and Kenya. Demographics As of October 2021, Burundi was estimated by the United Nations to have a population of 12,346,893 people, compared to only 2,456,000 in 1950. The population growth rate is 2.5 percent per year, more than double the average global pace, and a Burundian woman has on average 5.10 children, more than double the international fertility rate. Burundi had the tenth highest total fertility rate in the world, just behind Somalia, in 2021. Many Burundians have migrated to other countries as a result of the civil war. In 2006, the United States accepted approximately 10,000 Burundian refugees. Burundi remains an overwhelmingly rural society, with just 13% of the population living in urban areas in 2013. The population density of around 315 people per square kilometre (753 per sq mi) is the second highest in Sub-Saharan Africa. Roughly 85% of the population are of Hutu ethnic origin, 15% are Tutsi and fewer than 1% are indigenous Twa. The official languages of Burundi are Kirundi, French, and English, the last having been made an additional official language in 2014. Virtually the entire population speaks Kirundi, and just under 10%