Year	% of total fuel combustion
1971	15.469613259668508
1972	17.315175097276267
1973	15.415821501014198
1974	8.739255014326647
1975	11.501210653753025
1976	10.54897739504844
1977	11.829025844930415
1978	9.655172413793103
1979	9.752438109527382
1980	8.603896103896105
1981	9.379509379509381
1982	7.775768535262206
1983	6.854219948849105
1984	6.0344827586206895
1985	6.400409626216078
1986	6.962327134000954
1987	5.968894493484657
1988	5.812525583299221
1989	14.441645675902603
1990	10.727406318883174
1991	10.476830087306917
1992	11.032531824611032
1993	11.394196744515215
1994	11.432460020415109
1995	11.182519280205655
1996	11.977797253870873
1997	12.57606490872211
1998	11.48720682302772
1999	11.925601750547044
2000	12.293974601459064
2001	11.416816662381075
2002	11.206030150753769
2003	8.395802098950526
2004	12.429378531073448
2005	13.73246024321796
2006	13.552143991529912
2007	12.602785702299043
2008	12.357352461688945
2009	10.624779385810095
2010	9.830205540661305
2011	10.144369586140519
2012	9.854014598540145
2013	10.828877005347593
2014	10.736307580703663