Year	% of total fuel combustion
1971	41.79331306990882
1972	39.28077455048409
1973	35.65426170468187
1974	37.91208791208792
1975	32.608695652173914
1976	32.51649387370406
1977	33.07560137457045
1978	33.19935691318328
1979	34.433608402100525
1980	35.599415204678365
1981	30.952380952380953
1982	29.152308752584428
1983	29.431000654022238
1984	28.598848368522066
1985	30.424093423478798
1986	27.104477611940297
1987	23.135198135198138
1988	26.781737193763917
1989	30.55126223596084
1990	27.37913486005089
1991	27.33009708737864
1992	26.344328965205605
1993	21.80385288966725
1994	22.20888355342137
1995	17.798235519754506
1996	21.400778210116734
1997	19.955323901712585
1998	19.571532316630353
1999	19.84181568088033
2000	18.720379146919434
2001	17.365641503572537
2002	16.021602160216023
2003	12.522686025408348
2004	14.273904656930284
2005	15.942401645667267
2006	16.600298656047784
2007	16.259765625
2008	15.859649122807017
2009	15.823970037453183
2010	15.62568008705114
2011	16.15598885793872
2012	16.173913043478258
2013	14.979195561719832
2014	13.594426661645642