The line graph illustrates how the production levels of three main fuels – petroleum, coal and natural gas – in a European country changed from 1981 to 2000.Overall, it is evident that petroleum and natural gas production increased throughout the period, while coal production declined gradually. Petroleum remained the dominant fuel, whereas natural gas started from the lowest level but showed the most significant growth.
At the start of the period, petroleum recorded the highest output, at roughly 100 tonnes, slightly above coal which stood at about 80 tonnes. Petroleum output peaked at approximately 130 tonnes in 1983 and remained fairly stable until 1986; it then dropped sharply to just under 100 tonnes by 1991. In contrast, coal production stayed around 80 tonnes in the early 1980s but declined to roughly 50 tonnes by 1987, recovering slightly that year before resuming a gradual downward trend. Despite these changes, petroleum consistently remained well ahead of coal throughout the period.
Natural gas began at the lowest level, at about 40 tonnes, and remained virtually unchanged for the first decade. It rose slightly around 1995 and then increased sharply towards the end of the period. By 2000, natural gas had overtaken coal and considerably reduced the gap with petroleum, although petroleum still remained the dominant fuel.