Year	% of total fuel combustion
1990	19.191919191919194
1991	20.94958394517866
1992	33.7593984962406
1993	38.57142857142857
1994	31.711145996860285
1995	13.004484304932735
1996	15.551537070524413
1997	12.407407407407407
1998	26.3986013986014
1999	12.987012987012985
2000	16.179775280898877
2001	12.23404255319149
2002	17.510548523206747
2003	18.06083650190114
2004	13.872832369942195
2005	14.928425357873213
2006	16.188524590163937
2007	17.785234899328863
2008	21.112696148359486
2009	22.54601226993865
2010	25.662251655629138
2011	25.79750346740638
2012	20.37617554858934
2013	23.085585585585584
2014	9.33014354066986