Year	% of total fuel combustion
1960	20.095408467501493
1961	19.19561243144424
1962	18.29465731246627
1963	20.25628388368655
1964	17.26618705035971
1965	16.596104995766296
1966	16.440366972477065
1967	17.849898580121703
1968	17.24678582627783
1969	17.50285062713797
1970	18.360914105594958
1971	36.488133137198936
1972	36.157749671569505
1973	35.41374508081774
1974	35.585346553088485
1975	35.9952279133463
1976	36.551195427227704
1977	36.842432692554
1978	36.88431557671792
1979	35.68020813536664
1980	34.52875644736204
1981	33.57440217788845
1982	33.659120039400314
1983	33.3975021266951
1984	33.59227552261887
1985	31.7740052678545
1986	31.288712009712317
1987	31.330160756775577
1988	31.01238157900791
1989	30.169583461037256
1990	23.487035885173256
1991	23.200877867830794
1992	23.418100740428713
1993	22.71862027842121
1994	22.752156227752362
1995	24.634401398669954
1996	23.117811780598775
1997	23.051970349750242
1998	23.293785297976456
1999	21.744942839945082
2000	21.47401363343494
2001	21.38730085013339
2002	21.263316866362803
2003	21.283952420955234
2004	23.178122486657216
2005	24.15525206107301
2006	24.204458920479823
2007	25.074836808046683
2008	25.375479401212424
2009	25.730295928319315
2010	25.685223755839566
2011	25.676628734604922
2012	24.773907335628934
2013	24.561760791278836
2014	24.723287719089473