Year	% of total fuel combustion
1960	35.37591859807801
1961	35.916412712233345
1962	33.89116935059467
1963	33.80365659777424
1964	31.68522362709945
1965	30.939621293319046
1966	29.437489281426853
1967	30.03814625436247
1968	29.589798740205868
1969	28.49813090962398
1970	31.059803713902422
1971	31.31277901785714
1972	29.41850279630753
1973	28.988080142023836
1974	26.412797774300124
1975	25.444413485650596
1976	24.532658895975366
1977	23.42912561890664
1978	22.711811188445232
1979	23.026649103252613
1980	21.834187868820738
1981	20.219896802816223
1982	18.91525106462633
1983	17.49925661611656
1984	17.51898490819956
1985	17.506245741539857
1986	17.40249187432286
1987	17.171325051759837
1988	17.041066312336504
1989	16.62144626636782
1990	16.490201362953837
1991	16.501321484659286
1992	16.145460032441814
1993	16.2453531598513
1994	16.509056521422856
1995	16.187138601717187
1996	15.53880475932937
1997	15.652833674209937
1998	14.691167387276098
1999	14.42559143708569
2000	14.329250074693755
2001	13.852153769463099
2002	10.859287699492851
2003	12.540384288386328
2004	12.34419746352107
2005	11.771348677134867
2006	11.29985424672055
2007	11.167892631307266
2008	11.48352352865752
2009	10.542396848644009
2010	9.765364275812496
2011	10.227155394940631
2012	10.622852566586582
2013	11.39590728753393
2014	11.488041093691477