Year	% of total fuel combustion
1960	19.7376267143709
1961	19.68312004875076
1962	21.64058283864004
1963	16.21488417939872
1964	21.672661870503596
1965	22.81964436917866
1966	24.844036697247702
1967	22.718052738336713
1968	23.26748196926936
1969	26.795895096921324
1970	26.2936695560809
1971	22.667793707598744
1972	23.17044898379743
1973	23.970671726165932
1974	24.159102546199318
1975	24.109539552448844
1976	24.32085671953637
1977	24.520513355363548
1978	25.14170413063707
1979	26.231871711022134
1980	28.3114783255453
1981	28.470930214067867
1982	28.88519765923017
1983	29.330436907064165
1984	29.495852583093836
1985	31.25638599300675
1986	32.58884269295109
1987	33.26731859245934
1988	33.74658942941671
1989	35.07385512972881
1990	44.0208723095801
1991	44.690390567691836
1992	45.75224870270643
1993	46.170048656719665
1994	46.68649797840292
1995	45.65214854099023
1996	47.49823607308739
1997	47.045963381300574
1998	47.81127141589344
1999	48.37706473931363
2000	49.277016454332326
2001	49.670653429060465
2002	50.17371693591022
2003	50.950241669406005
2004	49.330320622887065
2005	49.41186420881781
2006	50.08572527199114
2007	49.609576284065334
2008	49.02071563088512
2009	49.073203321094105
2010	49.86699718501323
2011	50.39327956942047
2012	50.8241659193672
2013	51.004344555284014
2014	50.73350520781873