Make comparisons

Two pie charts given compares the percentages of energy that was produced in a nation over two separate years (1983 and 2003).
Overall, it is evident that the amount of energy generated was allocated for all categories, except hydropower, changing quite significantly over a 20-year period.
It is clear from both two charts that, although there was a slight fall of 4% from 42% to 38%, oil still accounted for the highest figure either in 1983 or in 2003. The percentage for manufacturing coal decreased by 10 per cent while the natural gas increased by the same figure.