Year	% of total fuel combustion
1986	13.29243353783231
1987	12.624113475177307
1988	10.208483105679367
1989	11.519078473722102
1990	14.401772525849335
1991	19.529411764705884
1992	16.626506024096386
1993	17.99698795180723
1994	16.402116402116402
1995	17.341862117981524
1996	20.053835800807537
1997	18.443427076520607
1998	19.069767441860467
1999	21.591695501730104
2000	15.220483641536273
2001	17.40591397849462
2002	17.56129887342611
2003	16.566466265865063
2004	16.01049868766404
2005	14.045307443365695
2006	12.397216951296647
2007	9.263959390862944
2008	10.95238095238095
2009	11.706349206349206
2010	12.03883495145631
2011	10.304601425793908
2012	8.809683927370546
2013	8.368495077355837
2014	7.523510971786834