Year	% of total fuel combustion
1960	33.26481671805413
1961	32.98357664233576
1962	32.13383838383838
1963	32.194567994700485
1964	34.1171935235158
1965	34.99058380414312
1966	33.9378492304676
1967	32.77261613691931
1968	33.86766408406804
1969	35.611172802596734
1970	35.80308304326206
1971	34.67605156037992
1972	33.63302321945118
1973	33.47616899714328
1974	32.765339650034385
1975	29.878787878787875
1976	31.511357251785853
1977	29.97487233525168
1978	29.158573537409683
1979	26.997807514931576
1980	26.733067729083665
1981	25.67156393984178
1982	26.63353579974232
1983	25.795795795795794
1984	27.906520031421838
1985	27.845468053491828
1986	26.79770841564599
1987	25.745310957551826
1988	26.17729876687057
1989	27.295380486869846
1990	26.46588235294118
1991	26.153984853948792
1992	24.51896646509071
1993	23.02809670493793
1994	23.778472532380526
1995	22.42228791543492
1996	21.316668093485145
1997	22.994370161857848
1998	23.307235653445755
1999	25.044420753375977
2000	25.82711715664765
2001	26.452119309262166
2002	22.87441860465116
2003	22.282560313362413
2004	20.619484963083014
2005	18.997017151379566
2006	20.359166426582156
2007	20.874273110086225
2008	19.612567463377022
2009	19.06143167927069
2010	19.791172282866636
2011	18.243964964751118
2012	18.732333115894757
2013	19.357601713062095
2014	20.68452380952381