Exam question 4: The two graphs show the main sources of energy in the USA in the 1980s and the 1990s.
The provided pie charts compare the expenses of the priority sources of energy in the USA falling into five categories namely oil, natural gas, coal, hydroelectric power and nuclear power in the 1980s and 1990s. At the first glance, oil was the major source of energy in the USA in this period.
From the pie charts, it is clear that oil had the greatest proportion in both charts, but it decreased slightly from 42 percents to 33 percents. Also, the usage of natural gas fell insignificantly by only 1 percent in this time. On the other hand, the figure for coal gradually rose 3 percents during those centuries. Obviously, the percentage of nuclear power doubled from 5 percents in 1980s to 10 percents in 1990s. Finally, there was no substantial variation in the percentage of hydroelectric power (5 % ) as a whole.
In conclusion, oil was the main source on energy in USA. In addition, nuclear power, in all probability, replaces other sources of energy in the future because of its popularity. ( 173 words)