The line graph illustrates the varying production frequencies of fuel in the United Kingdom from 1981 to 2000.
Overall, there were three types of changes in all the categories included, with fluctuations in petroleum, an increase in gas, and an unstable downward trend in coal. It is evident that both petroleum and gas had higher figures in the final year compared to the initial year, with petroleum consistently having the highest energy units over time.
Initially, coal production from 1981 to 1986 experienced a significant decrease after a stable increase in the first few years, almost halving from the starting number of 80 units. In contrast, petroleum saw a dramatic increase in the same period, rising from around 85 to 140.
On the other hand, gas production appeared relatively stable and unchanged, but in 1991, natural gas units surpassed coal and experienced a steep increase over the following 9 years to reach approximately 100 units. Additionally, petroleum showed fluctuating patterns from 1991 to 2000, remaining the highest produced fuel throughout the entire period.