The four pie charts illustrates how many sources of electricity generation was used in two different countries: in Germany and New Zealand, over a 30-year period; in 1980 and 2010.
Overall, the total number of units increased significantly, with coal being used the most as an energy resource in New Zealand. Additionally, the amount of units doubled in Germany.
To begin with, coal was the most prefered for use as an energy generation source in both years. While the quantity of units for hydro and natural gas was equal with the number of a third in 1980, the former went up to above 40, and the latter decreased by 15, making it in the last place. When it comes to the remaining one; petroleum, the number went down considerably, from eleven to two.
The number of coal units stood samely at just below a third, while the number for nuclear experienced a significant increase, from twenty to just over a hundred and a half in Germany. In contrast, it is evident that the quantity of both nuclear gas and hydro witnessed a notable decrease; the former declined from below 30 to two, the latter also diminished from five to two. Besides, the amount of petroleum ranked in the second place at above 20 in both years, with not changing excessively.