The pie chart illustrates the main sources of energy production for the United States in the years of 1980 and 1990.
Overall, the data indicates that oil constituted the primary source of energy in both years, while hydroelectric power produced the least energy. The comparison between the two years show that there was a decrease in production using oil and natural gas, whereas an increase can be observed the numbers for coal and nuclear power.
The amount of energy produced by petroleum accounted for 42% in 1980, but it reduced to a third of the American energy matrix in 1990. Conversely, the proportion of energy generated by hydroeletric dams remained constant in both years, at 5%.
The energy produced by natural gas, which was the second largest source, experienced a slight fall from from 26% in 1980 to a quarter (25%) in 1990. In contrast, production by coal grew from 22% in 1980 to 27% in 1990. Lastly, there was a significant increase of 5 percentage points in energy production by nuclear sources, reaching 10% in the second year.