The graph illustrates the different energy sources like oil, natural gas, coal, and hydroelectric power, nuclear power, for the USA in two different years, 1980 and 1990.
Overall, the main source remained to be oil in both years, though the production reduced in 1990 along with natural gas, while the source contributing the least was hydroelectric power, whose production remained the same. The remaining two sources (coal and nuclear power) had an incline in the production.
It is noticeable that the source producing the most for the USA was oil at 42% in 1980 and 33% in 1990, while at the same time the production by hydroelectric power remained a stagnant low of 5% in both years.
The other source that underwent a drop in production was natural gas (26% to 25%), while on the other hand, coal and nuclear power experienced an incline of 22% and 5% in 1980 to 27% and 10% in 1990 respectively.