Brunei has the second-highest Human Development Index among the Southeast Asian nations, after Singapore, and is classified as a developed country. Crude oil and natural gas production account for about 90% of its GDP. About  of oil are produced every day, making Brunei the fourth-largest producer of oil in Southeast Asia. It also produces approximately  of liquified natural gas per day, making Brunei the ninth-largest gas exporter in the world.  ''Forbes'' also ranks Brunei as the fifth-richest nation out of 182, based on its petroleum and natural gas fields.