The pie charts present changes in percentage of primary sources of energy in the USA between 1980 and 1990.
Overall, was the main source of energy in both years, despite the decrees in 1990. Natural gas and coal were accounted almost half of all resources. The least used were hydroelectric and nuclear power.
In 1980 Natural gas and coal together were equal almost 50% of total usage of resources, 26% and 22% respectively. Oil was the main resource of energy in the USA and had 42%. 10% of total resources were equally divided between hydroelectric and nuclear power.
In 1990 Oil experienced significant decrease and dropped by 9% from 42% to 33%. At the same time nuclear power underwent a sharp increase and rosed twofold, from 5% in 1980 to 10% in 1990. Natural gas and Coal recorded slight changes. Natural gas lost 1%, while Coal grown by 5% and reached 27% in 1990. Hydroelectric power remained stable at the same number.