 Kigali is the economic and financial hub of Rwanda, serving as the country's main port of entry and largest business centre.The NISR does not maintain detailed economic data for subnational entities in Rwanda, but economists have used various measures to estimate the city's output.A 2015 working paper by the World Bank Policy Research unit used the amount of light visible at night in different regions as a proxy for relative gross domestic product (GDP), and found that the three districts of Kigali represented 42% of Rwanda's total night-light output.