The two pie charts illustrate the major sources of energy: oil, natural gas, coal, hydroelectric power, and nuclear power in the USA, over two distinct years, in 1980 and 1990. Overall, oil was the most popular source of energy in the given years. The proportions of coal and nuclear power increased, whereas the percentages of oil and natural gas usage decreased at various rates throughout the given period. In stark contrast, the figure for hydroelectric power remained unchanged in both years.
In terms of increases, in 1980, the consumption of coal accounted for 22%, and it was followed by a noticeable growth to 27% in 1990. Similarly, the proportion of nuclear power doubled in a decade, comprising 10% in 1990.
Regarding decreases, starting at 42%, the percentage of oil experienced a significant fall to 33% in 1990, but it still constituted the largest segment. In 1980, the figures for natural gas made up 26%, after which it fell slightly to 25%, being responsible for a quarter of total energy usage in 1990. Hydroelectric power, on the other hand, remained unchanged, 5% equally in both years.