The graph gives information about amount of extracted petroleum, coal and natural gas in the UK from 1981 to 2000, measured in energy units.
It is noticeable that petroleum and natural gas have upward trend, as opposed to coal. Also, fuel with less production level at the beggining was natural gas, but coal overtooked it at the end.
The most valuable fuel group for the UK are petroleum and natural gas. In 1981 the former was stood at about 90 units, the latter at 39 units. After smooth increase from 1981 to 1983 petrolium was at 140 units. It is level remained constant until in 1987 it started to drop steadly. In the next 9 years production normalized to 140 units and generally remained on that level not to mention some fluctuations at the 1999.
Natural gas was stable at 40 units from 1981 to 1990. Then until 2000 year, it is production level rose gradually to about 100 units.
The least significant fuel int the UK appeared to be coal. It was stood at 80 and in from 1983 to 1984 dropped dramatically to about 35 units. In the next 2 years level increased to 60 units and unchaned until 1989. From that time it decreased steadly to about 30 units in 2000.