Year	% of total fuel combustion
1960	5.702153472854108
1961	5.326054883446445
1962	5.450236966824646
1963	4.659798754192619
1964	4.19061302681992
1965	3.9794168096054885
1966	3.9682539682539675
1967	3.755506607929516
1968	4.425489212242849
1969	5.467323840817818
1970	5.365351085750517
1971	7.145655410170022
1972	8.192923336141535
1973	8.666352180066042
1974	9.222642586908417
1975	10.294898036540067
1976	10.76277813321959
1977	9.0272261139597
1978	9.70201454952434
1979	9.444807315480078
1980	8.750687947165655
1981	8.106409719312946
1982	7.896492919107288
1983	9.192670397914588
1984	9.367144758243384
1985	10.213227322009399
1986	11.031751644155294
1987	11.780897330030282
1988	5.0806057645334635
1989	4.960371686253075
1990	5.15015533310321
1991	5.429209938214801
1992	5.305689872160032
1993	5.379442843419787
1994	5.017278894150774
1995	6.48199107197456
1996	6.544971405464735
1997	5.96609760511552
1998	5.874563621042494
1999	6.02064933449434
2000	6.056102545049226
2001	5.7314508861519995
2002	5.2890381386423595
2003	5.1363609589444525
2004	5.0845481049562675
2005	5.28710855637387
2006	4.744637698973635
2007	4.648318042813456
2008	4.638139874611964
2009	4.707873620862587
2010	5.165921393269002
2011	4.8468742090609975
2012	4.825685721609846
2013	4.842024145902903
2014	4.530133477147095