Year	% of total fuel combustion
1971	4.712041884816754
1972	4.975124378109454
1973	4.807692307692308
1974	4.587155963302752
1975	4.329004329004329
1976	4.255319148936168
1977	4.382470119521913
1978	4.347826086956521
1979	4.524886877828057
1980	4.566210045662098
1981	4.797047970479704
1982	5.194805194805193
1983	4.666666666666665
1984	4.972375690607735
1985	5.263157894736843
1986	5.3811659192825125
1987	5.1724137931034475
1988	5.020920502092049
1989	4.924242424242423
1990	4.724409448818898
1991	4.8245614035087705
1992	5.223880597014925
1993	5.51470588235294
1994	5.78231292517007
1995	6.230529595015577
1996	6.267806267806267
1997	6.11111111111111
1998	5.311355311355311
1999	5.460750853242321
2000	10.642570281124497
2001	9.306569343065693
2002	2.5411061285500747
2003	2.652106084243371
2004	3.209459459459459
2005	3.125000000000001
2006	2.7096774193548394
2007	2.860548271752086
2008	3.47938144329897
2009	3.4594594594594583
2010	2.392344497607655
2011	2.865064695009242
2012	2.9757243539545812
2013	2.637362637362638
2014	1.754385964912281