The first graph is a line graph. It shows the price of coal per ton over a five-year period. It also exhibits the cost for other fuel. The US dollar isthe unit.
The price of coal per ton increased from 52 dollars in 2004 until to a figure of 75 dollars in 2006. It slipped to 70 dollars in 2007. It recovered in 2008,with a cost over 80 dollars. Other fuels costed less than coal during the whole period. Between 2004 and 2005, the cost of other fuels rocketed. In 2005 it was over 50dollars. Then the price of other fuels stayed the same for one year. In 2007, it plummeted to 40 dollars. It rallied in 2008 and reached 45 dollars.
The second graph isa bar chart. It shows the quantity of coal which was bought from 2004 to 2008. It also indicates the quantity of other fuels during the same period.
Between 2004 and2008, the bought quantity of coal was much higher than the amount of other fuels. It was 50'000 tons at the beginning of the five-year period. It was slighty weaker in2005. It recovered in 2006 and shot up until to 70'000 tons in 2007. It crashed at the end of the period and it plunged to 50'000 tons. The quantity of other fuelsremained stable at 20'000 tons between 2004 and 2008.
The requested quantity of coal is linked to the price. The demand is really high when the price is low. You canobserve this phenomenon in 2007. The price of coal sinked to 70 dollars whereas the demand rose from 60'000 to 70'000 tons within one year. According to this rule, when theprice of coal was over 80 dollars in 2008, the demand fell.
Finally, it’s better to buy other fuels. In the one hand, it costs less. In the other hand, it’s less polluant.