Year	% of total fuel combustion
1990	62.312161891404536
1991	61.043550566469186
1992	62.96210986986065
1993	61.393497013934976
1994	66.05217934697704
1995	64.43624868282403
1996	62.895692786715095
1997	65.20020622100017
1998	63.901225794990225
1999	64.90384615384616
2000	65.82229898292073
2001	67.4459724950884
2002	66.83733753446238
2003	66.18649016935954
2004	67.40727139184722
2005	65.53353935648065
2006	64.19709942337934
2007	62.50897343862167
2008	61.25941136208076
2009	61.58111250223573
2010	62.12829936518543
2011	58.61584401897066
2012	57.26895119418485
2013	56.129807692307686
2014	57.16524464565558