Qatar imports the majority of its food. Agriculture is limited to fruits, vegetables, and livestock, and there is some fishing. Oil and natural gas, the mainstays of the economy, account for roughly 85% of the country's export earnings. Although total oil reserves are somewhat modest in comparison to other Persian Gulf countries, Qatar is one of the largest natural-gas producers in the world. The vast North Field gas reserve, an underwater field northeast of the Qatar peninsula, began production in the 1990s. Natural gas, crude oil, refined petroleum, and petrochemicals are produced, and ammonia, fertilizers, and steel are some of Qatar's developing diversified industries. The country has also become a regional banking center. Native Qataris have one of the highest per capita incomes in the world. In addition to oil and gas products, steel and fertilizer are exported, while machinery, transportation equipment, food, and chemicals are imported. Japan, South Korea, France, and the United States are the major trading partners.