The graph illustrates the main fuels’ production levels in a European country from 1981 to 2000. Overall, the tonnes of coal and natural gas experienced a downward trend, while the reverse was true for petroleum. In 1981, petroleum increased from 100 to 130 tonnes. It then remained stable for 4 years. From 1987 to 1989, petroleum declined from 130 to 100 tonnes. It remained stable before 1992. In 1992, petroleum fluctuated, and in 2000, it reached 120 tonnes.
Coal production was at 80 tonnes between 1981 and 1984. In 1984, it decreased to approximately 30 tonnes. Then, from 1985 to 1987, it increased. In 1987, coal production reached almost 70 tonnes. Between 1987 and 1991, it fluctuated and then started to slow down. In 1997, coal and natural gas production overlapped significantly. Eventually, in 2000, coal production reached almost 40 tonnes.
Natural gas had the lowest level among the other main fuels. From 1981 to 1994, it remained stable at 40 tonnes. Unexpectedly, in 1994, it increased, and in 2000, natural gas production reached 80 tonnes.