The graph illustrates the percentage of four different types of fuel—wood, coal, oil, and gas—used between 1800 and 2000. Overall, there is a clear shift from wood to coal and later to oil and gas as the dominant sources of fuel over the two centuries. This transition reflects significant technological and industrial advancements.
Initially, in 1800, wood was the primary fuel, accounting for nearly 100% of usage. However, its usage declined sharply throughout the 19th century, reaching almost zero by 1900. This decline coincided with the rise of coal, which began increasing around 1825 and peaked at approximately 70% around 1900. Following this peak, coal usage started to decrease steadily, falling to nearly zero by the year 2000.
In contrast, oil and gas emerged much later. Oil usage began rising in the early 1900s and saw a significant increase, surpassing coal around the mid-20th century. By 2000, it became one of the most dominant fuels worldwide. Gas followed a similar trend but remained consistently lower than oil, showing a gradual increase from the mid-20th century onward.
In summary, the graph highlights a significant transition from wood to coal in the 19th century, followed by a shift to oil and gas in the 20th century, reflecting changes in industrialization and technological advancements across the world.