The dual pie charts depict data pertaining to the five primary energy sources utilized by the United States in the years 1980 and 1990.
In 1980, the primary energy source was oil, accounting for 42% of the total energy mix. Hydroelectric power and nuclear power each contributed a modest 5% to the energy supply. A decade later, in 1990, oil maintained its dominant position, comprising approximately 25% of the energy sources. Natural gas also played a significant role, providing around 25% of the energy in both 1980 and 1990.
With respect to coal, there was a notable 5% increase in its participation from 1980 to 1990, reaching 27% in the latter year. While hydroelectric and nuclear power remained relatively minor contributors to energy sources, nuclear participation experienced a 5% rise in 1990 compared to 1980. Hydroelectric power, however, maintained a steady 5% share in both years.
In both years, oil was the primary energy source, with hydroelectric and nuclear power contributing insignificant amounts.