Year	% of total fuel combustion
1971	2.456140350877194
1972	2.4853801169590644
1973	2.615933412604042
1974	2.608695652173914
1975	2.4976873265494905
1976	2.62582056892779
1977	2.97441998810232
1978	3.03030303030303
1979	4.081632653061225
1980	3.9842209072978307
1981	4.059301094246384
1982	4.436113714464229
1983	2.2397094430992732
1984	1.541994750656167
1985	2.4229074889867857
1986	0.5282271376691983
1987	2.5665704202759083
1988	1.7463235294117654
1989	2.4743512371756164
1990	0.035637918745546907
1991	0.030422878004257907
1992	0.05049229992426217
1993	0.02765486725663599
1994	0.06559527714004673
1995	0.061031431187062085
1996	0.05492996429552389
1997	0.0483442107807596
1998	6.845317060228176
1999	0.53258939893482
2000	2.6965265082266914
2001	1.7810159886662629
2002	1.5667841754798282
2003	1.1840888066605006
2004	2.006258052641266
2005	3.7765957446808516
2006	5.511811023622048
2007	6.725514922236234
2008	4.833206974981047
2009	2.097583219334245
2010	9.072978303747535
2011	7.50864482134036
2012	10.350821744627051
2013	11.405921371946286
2014	10.754654255319148