Year	% of total fuel combustion
1960	29.951948745328348
1961	28.880675818373806
1962	27.559912854030504
1963	27.904118008604794
1964	27.658338175479365
1965	24.455077086656036
1966	25.458715596330272
1967	24.153757888697648
1968	22.97965915338098
1969	21.732444900051252
1970	21.88914027149321
1971	21.09422492401216
1972	20.807453416149066
1973	20.252438324727482
1974	18.2614133833646
1975	16.81068342498036
1976	13.499633162142333
1977	13.67851622874807
1978	13.710247349823321
1979	14.79245283018868
1980	15.353697749196144
1981	14.245014245014245
1982	11.14488348530902
1983	10.400866738894909
1984	11.98019801980198
1985	12.100677637947726
1986	13.486513486513488
1987	13.375796178343949
1988	14.387031408308006
1989	15.051740357478833
1990	16.10800744878957
1991	16.47373107747106
1992	16.040329972502292
1993	15.789473684210526
1994	13.468992248062017
1995	11.070559610705596
1996	8.795180722891565
1997	5.769230769230769
1998	2.247191011235955
1999	2.4161073825503356
2000	2.853598014888337
2001	4.7180667433832
2002	12.286324786324789
2003	11.788617886178864
2004	12.19946571682992
2005	11.759581881533101
2006	12.577502214348984
2007	11.880261927034612
2008	10.357815442561206
2009	12.313803376365442
2010	12.018779342723004
2011	10.371075166508088
2012	10.755813953488373
2013	7.6765609007164795
2014	8.324324324324325