The line graph compares the figures for energy units that three main kinds of fuel in the UK were produced over the period of 19 years, starting in 1981.
Overall, it can be seen from the graph that the number of petroleum-generated energy units was the highest every year during the period. The production levels of the other two kinds of fuel had replaced each other’s rank throughout the given period.
To start with, in 1981, petroleum showed the highest level of production, which is about 90 energy units, followed by that of coal and natural gas, with approximately 80 and 40 respectively. After experiencing ups and downs, petroleum was still the most important fuel used to generate energy compared to other fuels, with the number of over 140 energy units in 2000.
Starting from being the second-most used fuel to generate energy, the number of energy units produced by coal fell significantly before rising to 60, then gradually decreased, as the same figures as natural gas in 1991, and hit the lowest point at just above 30 energy units by the end of the period. In contrast, the production levels of natural gas, although being the weakest in 1981, remained unchanged until 1990, and increased dramatically in the following years, reaching a peak at roughly 100 energy units.