Year	% of total fuel combustion
1971	14.323901421306559
1972	14.750631498560772
1973	14.18055628581944
1974	14.407387913297288
1975	14.536447879745483
1976	14.509148887707843
1977	13.929997650927886
1978	12.885482416591524
1979	12.459033053022026
1980	11.278370153553094
1981	10.67942419496707
1982	10.395434162250305
1983	10.976487734639765
1984	11.591332115230273
1985	11.294877621242614
1986	10.579543485452339
1987	10.585316141610173
1988	10.15330766538327
1989	10.677323361335684
1990	10.277154546654348
1991	10.556784850512017
1992	11.105622787519552
1993	10.824520582689148
1994	11.821302320815617
1995	11.764647120523449
1996	12.358306126183392
1997	12.230993241634462
1998	11.936204146730462
1999	11.560871167582174
2000	11.89736732984116
2001	11.39229408107634
2002	11.610584276537166
2003	11.394393964098839
2004	11.741892203517747
2005	11.564457202505217
2006	11.54264658604743
2007	11.649289490590391
2008	10.737732279959946
2009	10.520203499986684
2010	9.739880244432596
2011	9.709887211660456
2012	8.939450099316662
2013	9.161603432849105
2014	8.727323572659287