Year	% of total fuel combustion
1971	15.68282849167787
1972	15.626597842760097
1973	15.4446106062349
1974	15.115324809951623
1975	15.173787471367394
1976	15.534669930305126
1977	15.630305045590578
1978	16.046563155113937
1979	16.391309799987464
1980	15.991522493950008
1981	15.915852700123496
1982	15.430457504355
1983	15.6639684970466
1984	16.036092168876273
1985	15.095805282237185
1986	14.066372545994916
1987	13.671347103081418
1988	13.626742172251697
1989	13.889297106648572
1990	10.599357761673312
1991	10.387507339154151
1992	11.345355942633786
1993	11.748924175605591
1994	12.816538478463892
1995	14.17022588996159
1996	14.802833759259856
1997	14.57994747959631
1998	14.19312348161362
1999	14.13042136576655
2000	14.117328220499067
2001	13.76406689590497
2002	13.90574862263123
2003	13.530898815188253
2004	13.323098569096787
2005	12.881088911288977
2006	12.758121459957838
2007	12.1788051521942
2008	11.648166524357881
2009	11.085943620545102
2010	10.622292417582706
2011	10.605021299645385
2012	10.068562752987344
2013	10.054420152091256
2014	9.605917406604153