Year	% of total fuel combustion
1990	28.318661204567245
1991	30.17953045880006
1992	33.330387443438916
1993	26.94063926940639
1994	23.68344132118673
1995	24.790882211720707
1996	25.346828374487394
1997	25.59024899450431
1998	25.761284637227067
1999	26.712419163257223
2000	27.36610169491526
2001	29.564371056517658
2002	29.465116279069765
2003	29.436042658311738
2004	31.398571754654842
2005	25.58432279794509
2006	27.12257893340409
2007	27.235231074015132
2008	25.62162895620611
2009	22.530468248877487
2010	23.02174484545762
2011	23.30566091748372
2012	22.086696125333237
2013	21.46630442985435
2014	23.46326202756405