Sources of energy produced in USA in 1980 and 1990

The pie chart compares five different types of power that were produced in the United States between 1980 and 1990.
In general, oil, natural gas, and coal accounted for the majority of total energy production, whereas hydroelectric power and nuclear power constituted the smallest proportions of the total.
Oil was mainly manufactured in the USA, which made up 42% and 33% of the total in 1980 and 1990, respectively. Besides, the exploitation of natural gas was recorded at 26% by 1980, and then slightly declined to 25% after 10 years. The last type of energy of the three biggest power manufacturers depicted was coal, which accounted for 22% and 27% in 1980 and 1990, correspondingly.
In terms of manufacturing, hydroelectric power and nuclear power were slightly different from one another. Hydroelectric power productivity remained the same in 1980 and 1990 at 5%, while nuclear power productivity increased from 5% in 1980 to 10% after 10 years.