Petroleum, otherwise known as "crude oil", has become the resource most used by countries all around the world including Russia, China (actually, China is mostly dependent on coal (70.5% in 2010)) and the United States of America. With all the oil wells located around the world energy security has become a main issue to ensure the safety of the petroleum that is being harvested. In the middle east oil fields become main targets for sabotage because of how heavily countries rely on oil. Many countries hold strategic petroleum reserves as a buffer against the economic and political impacts of an energy crisis. All 28 members of the International Energy Agency hold a minimum of 90 days of their oil imports, for example.