The US's economy relies almost exclusively on nonrenewable fossil energy sourses. In 1976, 93.2 percent of the nation's primary energy source was fossil fuel; the remaining 6.8 percent was supplied by electricity generated from hydroelectric and nuclear power. In order to meet the growing demand for fossil energy, petroleum imports have been increasing- in 1976, 44.5 percent of the petroleum consumed in the US was imported and 22.4 percent of all US energy consumed in the US was imported. The ability to reduce imports in the near term to an acceptable level with resoect to improving balance of payments and providing for national secutiry will depend on energy conservation and increased coal usage.