The dramatic change in supply conditions for energy resources since 1973 had a substantial effect on the productive capabilities of the U.S. economy. Higher prices of energy resources, relative to the prices of labor and capital resources, resulted in a loss of economic capacity and higher output prices. It has been estimated that four to five percentage points of both the higher price level and reduction in national output in 1974 were due to the increased scarcity of energy resources entailed by the quadrupling of OPEC petroleum prices.