The given line graph illustrates the amount of electricity generated by three various energy sources namely coal, natural gas and petroleum to supply the city of New York over a period of 20 years, starting from 1980.
Overall, the amount of all surveyed electricity witnessed an increasing trend, with the exception of coal. In addition, petroleum was consistently highest during the examined period.
In 1980, petroleum produced 350 millions kWh of electricity, which was approximately 3.5 times higher than that of natural gas (100 millions kWh). From 1980 to 1985, petroleum increased sharply to 600 millions kWh, while natural gas did not change. Subsequently, the figure for petroleum dropped back to 350 millions kWh in 1990, after which it began to rise steadily to the highest point of approximately 700 millions kWh in 2000. Therefore, the data for natural gas rose sharply to 500 millions kWh by the end of the period, claiming the second place.
Moving to the remaining, coal started at the second position in the beginning at 200 millions kWh. From 1980 to 1985, coal rose minimally to 300 millions kWh, after that decreased back to 200 millions kWh. In the last 10 years, coal remained relatively stable at around 200 millions kWh.