Papua New Guinea (PNG) is richly endowed with natural resources, but exploitation has been hampered by rugged terrain, land tenure issues, and the high cost of developing infrastructure. The economy has a small formal sector, focused mainly on the export of those natural resources, and an informal sector, employing most of the population. Agriculture provides a subsistence livelihood for 85% of the people. Mineral deposits, including copper, gold, and oil, account for nearly two-thirds of export earnings. Natural gas reserves amount to an estimated 227 billion cubic meters. A consortium led by a major American oil company is constructing a liquefied natural gas (LNG) production facility that could begin exporting in 2014.