The graph below depicts the production levels of the main kinds of oil in the UK from 1981 to 2000. Overall, the amount of energy gained by petroleum and natural gas increased to 2000, whereas energy units from coal declined.
Taking the details, the petroleum production level was approximately 90 energy units at the start of production. From 1981 it started to grow steadily, reaching its peak of 140 energy units in 1984 and holding this level for over 4 years. Then, it declined to 100 energy units and started to grow until 2000. Starting from 1981 the production level of natural gas rose and reached its peak in 2000, making 100 energy units.
As regards coal, the amount of energy units was constant between 1981 and 1983. Then, it decreased to approximately 40 energy units in 1984 and grew to 60 energy units. The next 14 years the production level of coal decreased steadily.
