The line graph compares the amount of electricity production in New York City using three different sources of power over a period of 20 years.
It is clear that petroleum power was by far the most important means of electricity generation over the period shown.While the amount of electricity produced by natural gas saw a significant increase ,there was an opposite trend in this figure for coal.
In 1980, the petroleum power was used to generate almost 400 millions kilowatt-hours,which was clearly higher than those of both the coal (roughly 200 millions kilowatt-hours) and natural gas (100 millions kilowatt-hours).Just 5 year later,the amount of electricity produced by petroleum surged to over 600 millions kilowatt-hours .Similarly,this figure for coal increased to about 300 millions kilowatt-hours,whereas it for natural gas remained exactly at 100 millions kilowatt-hours.
However,electricity production from petroleum sources had declined dramatically to relatively the same number in 1980,before rising sharply to more than 700 millions kilowatt-hours at the end of the period.After staying stable for 5 years,the amount of electricity produced by natural gas experienced a big jump from 100 millions kilowatt-hours to over 500 millions kilowatt-hours in 2000.By contrast,this figure for coal substantially dropped to 200 millions kilowatt-hours in 1990 and finally fell slightly toward the end of period.