The given graph illusttrates the UK production extents of the prior kinds of fuel, measured by one energy unit over a approximately 20 years period.
Overall, a petroleum remained as the source of the most high levels of energy both in 1981 and in 2000.
First, in 1981 natural gas was on the low point compared with other types of fuel. It has shown a stability, demonstrating slightly altered results close to 40 energy units untill 1990. Starting from this time it started increasing step by step and reached its peak 100 energy units. When it comes to a coal, in 1981 it showed doubled energy units of natural gas, but time passing by near to 1984 it experienced dramatical shift, decreasing twice in level. Then it increased by 20 energy units in 1986. In 2000 it became the most less productive fuel, experiencing slowly going down.
Furthermore, a petroleum has experienced a couple of rises in this period. It itcreased in 1984 and 1992 right after rapid fall.
