Year	% of total fuel combustion
1971	19.173200285103352
1972	18.964401294498384
1973	19.26153846153846
1974	18.84150222788033
1975	17.81456953642384
1976	17.547055251973287
1977	16.675869685256764
1978	14.850000000000001
1979	16.751269035532996
1980	16.572077185017026
1981	16.92192753081808
1982	17.91487957769713
1983	18.389385991977786
1984	14.972776769509982
1985	16.82090364725095
1986	16.44687733266982
1987	13.815484469170144
1988	15.246465418418037
1989	16.8310322156476
1990	14.604316546762588
1991	12.757731958762886
1992	23.755656108597282
1993	25.335689045936395
1994	18.933823529411764
1995	18.552875695732837
1996	14.853689567430026
1997	13.102178582387234
1998	16.632337796086507
1999	12.771929824561404
2000	16.439835817671206
2001	14.177618478693748
2002	12.772883952508618
2003	15.773698014237542
2004	14.212024190679474
2005	17.794253938832252
2006	15.752712141477188
2007	13.305674914802196
2008	12.924409668855667
2009	12.496812037745473
2010	13.602702351565545
2011	15.26755031909671
2012	15.229016507788886
2013	14.60166468489893
2014	16.71700743494424