Year	% of total fuel combustion
1990	37.110232762406675
1991	37.05335291238375
1992	25.48872180451128
1993	29.795918367346935
1994	41.60125588697017
1995	12.556053811659194
1996	18.26401446654611
1997	19.62962962962963
1998	20.454545454545453
1999	24.89177489177489
2000	18.876404494382022
2001	16.48936170212766
2002	31.434599156118143
2003	31.93916349809886
2004	30.63583815028902
2005	15.132924335378323
2006	14.959016393442623
2007	16.2751677852349
2008	14.978601997146935
2009	6.595092024539878
2010	10.761589403973511
2011	7.905686546463245
2012	15.987460815047022
2013	8.333333333333332
2014	19.617224880382775