The chart above illustrates a production levels of the main fuels in the UL over the period from 1981 to 2000.
Overall, it is evident that petroleum and natural gas experienced a general upward trend, whereas coal showed thw oppositw pattern. Additionally, petroleum recorded the highest figures throughout the period, while coal remained the lowest.
At the beginning of the period, petroleum stood at approximately 80-100 energy units in first year. This figure then rose gradually to 140 by 1986 then fell down to 100 energy units around 1991 and growth again to 140 energy units by 2000. Meanwhile, coal started at 80 energy units and experienced a steadily decrease before reaching around 20-40 energy units between 1981 and 1986 and ended up with significantly plummet in last year.
Turning to natural gas, the figure was 40 energy units in 1981 then it subsequently remaining stable until 1991. Also this pattern was strongly rose and peaking at 100 energy units in 2000.
