Year	% of total fuel combustion
1960	2.995465173953096
1961	2.783898532810232
1962	3.007178200571464
1963	3.147326719263197
1964	3.2091378841446834
1965	4.020167396043061
1966	4.185184549650808
1967	4.189071986123154
1968	4.341591513769394
1969	4.309624828784284
1970	2.7584091936212785
1971	2.660225442834138
1972	1.7040358744394615
1973	1.7174218170922104
1974	1.7998487522056972
1975	2.3735935546603684
1976	2.2784679622660975
1977	2.3921184925267394
1978	2.677000135372953
1979	2.691770597582703
1980	2.6959753190295888
1981	2.716695228646162
1982	2.7618185512922357
1983	2.4219570763920153
1984	2.540500736377025
1985	2.4749742381863666
1986	2.4409477042187886
1987	2.369693522008105
1988	2.4526754839399656
1989	2.4337212914070627
1990	2.532362016395538
1991	2.9516802971322456
1992	2.5684587420763236
1993	2.639019792648444
1994	1.7740054673013335
1995	2.1102631988786795
1996	1.7013940938390064
1997	1.5319381753522083
1998	1.519916142557654
1999	1.4828689612112709
2000	1.4851770123764743
2001	1.4340665496508191
2002	1.1214126336846975
2003	0.9995115169278174
2004	1.0907520744940487
2005	1.2049326932128397
2006	1.0459504628847196
2007	1.001246763210894
2008	0.8050864139207118
2009	0.7532874684315954
2010	0.7948658794907822
2011	0.8255792738551353
2012	0.8114775383017399
2013	0.9650020011562236
2014	0.9587092977638307