The pie charts below compare the changes in the consumption of five main energy sources (oil, natural gas, coal, hydroelectric power and nuclear power) in the USA in years 1980 and 1990.
Overall, oil remained the dominant source of energy in both years, although its share declined, while the contribution of coal and nuclear power increased significantly.
By far, in 1980, oil accounted the largest proportion of energy consumption at 42%, followed by natural gas at 26% and by coal at 22% from the total energy consumption. For hydroelectric and nuclear powers at 5% for both of them.
In 1990, the pattern changed considerably. Oil remained being the largest energy source group, although its amount fell to 33%. In contrast, positions for natural gas and coal flipped, coal became the second largest source at 27%, and natural gas – the third group at 25%. The consumption of nuclear power doubled, making it forth group, and the usage of hydroelectric power remained at 5%.