Year	% of total fuel combustion
1990	7.967084346362445
1991	6.072252113758648
1992	6.364922206506366
1993	4.738955823293172
1994	4.598737601442743
1995	3.6155747836835608
1996	3.8433111603843315
1997	2.8560548362528566
1998	2.971428571428574
1999	3.610248447204969
2000	6.080586080586082
2001	4.723190089043746
2002	1.4896119168953366
2003	1.0064701653486698
2004	1.4233576642335777
2005	2.9300241296104796
2006	0.5784280367471922
2007	2.43536905207943
2008	2.777777777777777
2009	4.1190864600326265
2010	4.462388440288994
2011	4.1603630862329775
2012	3.876773970231913
2013	3.9728353140916806
2014	3.6050665800584594