Year	% of total fuel combustion
1960	20.129241330380346
1961	20.075129694898767
1962	20.64032245629071
1963	20.568030628037693
1964	19.341567821750623
1965	19.104786344725685
1966	18.64724668566621
1967	18.393782755505512
1968	18.074615955266772
1969	18.023137890220827
1970	19.84151758631779
1971	19.66159666841494
1972	19.465848089138454
1973	18.47467678562695
1974	17.797846032112226
1975	18.105772113050694
1976	18.18791946308725
1977	17.429541432406726
1978	17.55569115361989
1979	16.825706924867095
1980	15.924653732903598
1981	15.482141803428883
1982	15.728811957634113
1983	15.45960671288483
1984	15.883266033876973
1985	15.98118819506164
1986	16.02630984913342
1987	15.586522801302934
1988	15.230712563621752
1989	14.563406505825034
1990	13.653188963631784
1991	13.99145886519763
1992	13.871297520548504
1993	14.250952823748742
1994	13.762529924741258
1995	13.835404573993518
1996	14.480236280847242
1997	13.692773942327388
1998	13.035244098141288
1999	13.2002228538708
2000	12.910214670744153
2001	12.991500645610392
2002	12.868220171098251
2003	13.05402521648064
2004	12.775987890089828
2005	12.57343926502335
2006	11.97930617839314
2007	11.414471137192574
2008	12.068926492100951
2009	12.679962591228627
2010	12.366632082630035
2011	11.805756496273794
2012	11.648793363566133
2013	12.326671256320362
2014	11.89292501766543