Year	% of total fuel combustion
1990	16.302610548748003
1991	16.22093023255814
1992	17.715112075198842
1993	19.420783645655877
1994	20.710059171597635
1995	22.584269662921344
1996	21.685393258426966
1997	23.39667458432304
1998	24.159402241594023
1999	25.775978407557353
2000	30.99415204678363
2001	34.62068965517241
2002	35.822959889349924
2003	36.72922252010724
2004	38.36898395721925
2005	39.577836411609496
2006	41.22042341220424
2007	44.856459330143544
2008	44.58438287153652
2009	43.31476323119777
2010	39.30778739184178
2011	38.41961852861036
2012	39.05579399141631
2013	39.94211287988422
2014	42.857142857142854