Year	% of total fuel combustion
1971	47.53702120473281
1972	47.064317723393046
1973	46.06463643196239
1974	46.543370912140134
1975	46.519587963338466
1976	47.46263997814977
1977	47.54465368700486
1978	46.13547734228453
1979	44.72693427807968
1980	43.715989383233754
1981	42.65516531178445
1982	43.078804822645466
1983	43.2323400477221
1984	43.55991691877935
1985	40.57175800668551
1986	40.300706834992916
1987	39.85424050316977
1988	38.923923649096736
1989	37.34619601322133
1990	35.715387078791615
1991	35.090694228208065
1992	34.665635983369384
1993	33.93613299795106
1994	33.99516171813334
1995	35.73802429520972
1996	32.6067025426383
1997	31.841957858773107
1998	32.4721951538181
1999	29.417025211666136
2000	28.3335301140016
2001	28.569003480006195
2002	27.592361443253267
2003	27.439238736787026
2004	30.608852279280363
2005	31.747454136252657
2006	31.490105536092766
2007	32.104512350777085
2008	33.06616903165609
2009	33.3269119390705
2010	32.41720747094669
2011	31.742068832513706
2012	30.87648583485266
2013	29.885919017513082
2014	30.406172967655753