Year	% of total fuel combustion
1971	7.248146532926297
1972	7.251521298174443
1973	6.770470214578976
1974	5.640749017492486
1975	6.153517820303053
1976	5.857440708887152
1977	5.083691120652106
1978	4.514167718251692
1979	4.2748433303491495
1980	3.885192286004285
1981	2.5072755764495187
1982	3.4910739586285073
1983	2.949076664801343
1984	2.8873642081189246
1985	2.447532452679133
1986	2.216666666666667
1987	2.93852914703235
1988	2.6729965426492597
1989	5.5830612029916775
1990	6.969282870892996
1991	7.361260293591119
1992	8.418079096045197
1993	7.261645624727906
1994	7.885368458526165
1995	6.937595646998809
1996	9.487964265034329
1997	10.576836004708865
1998	11.453150912106135
1999	11.222396524677206
2000	10.957792207792208
2001	12.642294220665502
2002	12.95644522657281
2003	12.804123711340207
2004	13.737201365187712
2005	13.015324843513923
2006	13.134704154427194
2007	14.381487889273355
2008	16.405479452054795
2009	19.168710468568477
2010	18.48582129481006
2011	17.354758961681085
2012	19.5013357079252
2013	21.63768115942029
2014	22.44718309859155