Year	% of total fuel combustion
1971	11.479435236341315
1972	12.38993710691824
1973	12.166003411028994
1974	12.699514226231784
1975	12.625368731563425
1976	22.599830076465594
1977	24.960753532182103
1978	24.029850746268657
1979	21.086036671368127
1980	24.8993288590604
1981	25.589005235602098
1982	25.06082725060827
1983	27.27272727272727
1984	29.706390328151983
1985	30.407343660355707
1986	30.66457352171638
1987	30.722891566265066
1988	38.70813397129187
1989	31.895573212258792
1990	28.078250863060987
1991	21.252927400468387
1992	17.194570135746606
1993	13.169114163903362
1994	15.890645023494235
1995	16.357012750455375
1996	18.225963094852702
1997	22.31382247870294
1998	26.063168366078095
1999	23.913583312639684
2000	25.983717774762553
2001	25.35355605656897
2002	27.25205527374497
2003	26.202321724709787
2004	27.941176470588236
2005	30.699203439119987
2006	32.76010318142734
2007	32.19734937075398
2008	29.895988112927192
2009	28.98745519713262
2010	32.90506780870807
2011	32.05669241181623
2012	33.2291165624499
2013	34.18704814643901
2014	34.89637848021771