Year	% of total fuel combustion
1971	20.642201834862384
1972	22.083333333333336
1973	19.367588932806328
1974	18.97810218978102
1975	20.496894409937887
1976	20.96317280453258
1977	15.733333333333333
1978	14.004914004914001
1979	11.056511056511056
1980	9.97624703087886
1981	12.141280353200884
1982	22.792607802874745
1983	26.923076923076923
1984	20.261437908496735
1985	16.705336426914155
1986	13.493975903614459
1987	8.735632183908047
1988	10.328638497652582
1989	12.5
1990	14.951456310679612
1991	13.926499032882012
1992	13.493530499075785
1993	12.966252220248666
1994	13.278688524590166
1995	12.77213352685051
1996	10.664605873261205
1997	11.710323574730355
1998	12.103746397694524
1999	13.149847094801222
2000	12.535211267605634
2001	12.334801762114537
2002	12.727272727272727
2003	12.148337595907927
2004	11.854460093896714
2005	11.797133406835721
2006	11.651469098277609
2007	11.677479147358666
2008	10.988074957410563
2009	12.258064516129032
2010	11.021897810218979
2011	11.36516476126429
2012	10.87866108786611
2013	11.827321111768184
2014	11.530054644808741