Year	% of total fuel combustion
1960	19.076081450714213
1961	18.566144090188477
1962	18.35568424260896
1963	18.97333699835074
1964	19.12061569518042
1965	18.787172011661806
1966	18.39295248264816
1967	18.000384726363375
1968	17.933251144769283
1969	17.822265625
1970	16.827500819343797
1971	16.64707915658486
1972	16.783604738439447
1973	16.837419197463106
1974	15.640940508888956
1975	17.34397677793904
1976	16.793915459997073
1977	18.3565434475291
1978	18.967913647789445
1979	19.869983041266252
1980	20.04391644614605
1981	20.611283000318075
1982	21.62273113802305
1983	22.009099830493355
1984	22.493930441395854
1985	23.305939812242272
1986	24.098843138969023
1987	24.24225709479026
1988	24.75865830379057
1989	24.478706255524934
1990	24.673122864702403
1991	25.217637665481895
1992	26.687752774032976
1993	27.38935047290589
1994	27.641524393466888
1995	26.649708214873556
1996	27.291227012360565
1997	27.47781433841859
1998	27.54365937188798
1999	27.835249042145595
2000	27.677190645000117
2001	28.20073322858639
2002	28.26769072261509
2003	27.358299822523758
2004	27.259936686598664
2005	26.937827354210953
2006	27.662227764663967
2007	28.25486019848643
2008	27.496851238512853
2009	29.146789708297486
2010	27.85220342443033
2011	28.41592666857634
2012	27.95569861967374
2013	29.84234234234234
2014	32.95486534672047