Year	% of total fuel combustion
1990	24.625
1991	26.921285514671638
1992	22.975517890772128
1993	20.41884816753927
1994	21.172638436482085
1995	20.426829268292686
1996	8.47457627118644
1997	6.650831353919242
1998	4.31924882629108
1999	4.130643611911624
2000	10.932944606413994
2001	9.851851851851851
2002	10.478199718706046
2003	2.6804123711340204
2004	5.33245556287031
2005	6.746532156368222
2006	6.468231253577561
2007	6.568946796959825
2008	6.32411067193676
2009	6.77882236516576
2010	7.857491459248416
2011	7.64957264957265
2012	8.360277136258661
2013	10.367271036727104
2014	9.805735430157261