These two pie charts depict major materials of power sources in the US in 1980 and 1990. It is clear from the graph that oil
was in more in common usage during thethese periods. According toAccordingly, whatit is shown that the oil suppliedsupply was the largest percentage
in 1980, but thethis percentage decreased by 9 % in 1990. Natural gas produced was the second-largest proportion
and coal supplieduse was third-ranked ofthe third ranking power sourcessource in 19981990. Natural gas had almost the same portion in both years.
Coal produceduse was 22% in 1980 and the ratio of coal suppliedsupply increased byto 27% in 1990. Hydroelectric energy
suppliedenergy supply had no change in the rates, which remainedremaining at 5% total of power sources used in both years. Nuclear power supplied hadsupply was 10 % in 1990, while nuclear use was 5% in the lastprevious decade. To sum up, we could say thethat the US depended on most of theoil as its main sources oilsource of power, but in the year 1990, it reduced dependingdependence on oil and expanded onto other resources.