The provided graph illustrates the levels of fuel production in the UK over the period from 1981 to 2000.
The graph outlines the production quantities of coal, natural gas, and petroleum in the UK from 1981 to 2000, measured in energy units (where 1 unit equals the energy from 1 million tons of oil). Coal production steadily declined from approximately 120 units to below 40 units. Natural gas production witnessed a significant rise from below 40 units to over 100 units. Meanwhile, petroleum production fluctuated between 60 and 100 units.
Petroleum consistently maintained the highest production levels throughout the entire period, surpassing coal and natural gas. Coal initially had a production level similar to petroleum in the early years, then experienced a sharp decline just before 1986 before gradually increasing and stabilizing by 1986. However, since 1991, coal production has been steadily decreasing. On the other hand, natural gas started with lower production levels but has been steadily increasing since 1991, nearly aligning with petroleum production and showing a more rapid rate of growth compared to coal.