The two pie charts show oil,natural gas,coal,hydroelectric power,and nuclear power,these five energy in the USA during two decades .
Overall,although the oil and natural gas expressed the highest percentage and both decreased, but the oil still remained the biggest source of energy.The rest of the three energy maintained the same proportion,in spite of they had gone up in these ten years.The hydroelectric did not change over the entire duration of the given time.
From 1980 to 1990,the oil had a dramatical decrease in nine percent higher compared to the natural gas dropped only one ratio.The third major of energy ,coal,it grew five percentage in two decades,same as the nuclear power had two times increase,in 1980 to 1990.In 1990,the lowest proportion of sources,hydroelectric,it used to had same share five percent with nuclear power in 1980,after 10 years,it still remained the rate,and was the least ratio of the five different sources in 1990.
