The two pie charts below gives information about how different percentage of six main sources of energy used in the USA in the years 1980 and 1990.
Overall, by looking at the charts it can be seen that the proportion of energy generated by coal and nuclear power increased, while the figures for the rest of energy sources had deceased or remained significantly. The percentage of oil was the most important sources during this period.
In 1980, energy produced by oil accounted for the highest proportion, at 42% of the total energy production in the USA. The figure of natural gas and coal were lower, at 26% and 22% respectively. Meanwhile, only 5% of the energy was generated by nuclear power and the remaining percentage was for hydroelectric power.
In 2005, the percentage of oil declined notably, but remained the highest figure in the chart, at 33%. The figure for coal rose slowly to 27%, while that for natural gas fall of 25%. There were gradually increase to 10 % in the figure for nuclear source, while the rate of hydroelectric unchanged sustainably.