Year	% of total fuel combustion
1971	10.790273556231002
1972	10.650069156293222
1973	9.36374549819928
1974	9.12087912087912
1975	9.213250517598343
1976	9.42507068803016
1977	9.536082474226806
1978	9.72668810289389
1979	9.827456864216053
1980	9.210526315789474
1981	8.946608946608947
1982	9.166092350103378
1983	9.287115761935906
1984	9.341010876519514
1985	9.40381069452981
1986	9.611940298507465
1987	10.198135198135198
1988	10.244988864142538
1989	10.14940752189593
1990	8.9058524173028
1991	9.95145631067961
1992	10.031631269769543
1993	10.55166374781086
1994	10.164065626250501
1995	10.16494054468738
1996	10.661478599221791
1997	10.908413998510797
1998	11.147421931735657
1999	11.24484181568088
2000	11.272850372376439
2001	10.717614165890028
2002	10.741074107410743
2003	10.949788263762855
2004	10.691650592449712
2005	10.41398817176652
2006	10.826281732205075
2007	11.5966796875
2008	11.83625730994152
2009	12.03183520599251
2010	11.621327529923828
2011	11.142061281337048
2012	11.53623188405797
2013	12.58173172181494
2014	12.483524759932216