We assume the oil embargo of the late '70s and early '80s caused the dip in consumption starting in approximately 1986. Energy use by sector for the U.S. Clearly transportation is where the U.S uses most of its energy. It should be noted that this includes transportation of manufacturing goods and farm production. It should be noted however, that the world has experienced temporary downturns of energy consumption without significant loss of productivity. The U.S. currently is by far the worlds leading consumer of energy.
Fossil fuels are by far the leading source of energy for the world currently.
Significant supplies of fossil fuels are found in only a handful of countries around the globe. The U.S. uses its energy primarly for transportation.