The line graph illustrates the amount of 3 popular fuels produced in a particular European nation between 1981 and 2000.
Overall, there was an upward trend in the production levels of petroleum and natural gas, with the natural energy sources witnessing the most significant increase, while a reverse pattern could be seen in that of coal. Notably, despite some considerable fluctuations, petroleum still became the dominant fuel throughout the surveyed period.
Regarding categories experiencing rises, nearly 100 tonnes of petroleum were produced, which were 60 tonnes higher than that of natural gas, at 40 tonnes. Then, the figure for petroleum production saw a growth of 30 tonnes and remained unchanged at 130 tonnes for around 4 years, with a subsequent pullback to its initial number, slightly fluctuating in the range of 95 to 99 until 1991. After all, the equivalent data bounced back up to its peak of roughly 130 tonnes. On the contrary, there was a stability in the amount of produced natural gas, at 40 tonnes, it eventually witnessed a twofold increase to over 80 tonnes in 2000.
As for the remaining group, coal production levels remained stable at 80 tonnes during the first 3 years, the figure remarkably declined and reached a low of 38 tonnes, ultimately surpassing the lowest level of natural gas, retaining its bottom-most position from 1996 onwards.