The pie charts illustrate the largest sources of power supply in the USA in the 1980s and 1990s.
It is noticable that the biggest proportion of energy was derived from oil in both decades , and the figures for it decreased significantly, whilst the percentage of power generated from nuclear energy doubled in 1990 in comparison with the data from 1980.
The oil was the most significant power supply in 1980, and the lowest amount of energy was coming from hydroelectric and atomic power, which were accounted for 42% and 5%, respectively. In 1990, the figures for petroleum showed a decline of 9%, whereas the percentage of nuclear power rose to 10%, and the amount of water energy remained the same, which indicates it as the smallest source of energy at the end of the decade.
The proportion of energy generated from charcoal was 22% in the beginning, and it increased to 27% in 1990. By contrast, the percentage of natural gas had slightly fell from 26% to 25%.