Year	% of total fuel combustion
1960	20.397864014239907
1961	20.633712890612077
1962	20.77649960217709
1963	19.8953815212387
1964	19.22961346469718
1965	18.987338263501602
1966	18.720843489955453
1967	18.80319001176809
1968	18.299740332822264
1969	18.38218884663257
1970	19.72575180472582
1971	19.713757281385583
1972	19.134788999389947
1973	17.5228303741694
1974	17.251358074833732
1975	17.512256973795434
1976	17.774496601385017
1977	16.617684801213382
1978	16.54163098591005
1979	15.335939132418426
1980	14.45855175300472
1981	13.695652173913048
1982	14.430544901285383
1983	13.881493909485451
1984	13.796933923594032
1985	13.254310783990089
1986	13.004229803561916
1987	12.660795281681319
1988	12.824747434481031
1989	12.746304727629152
1990	11.842848580133552
1991	12.102198661684193
1992	12.129929600881649
1993	12.323660020798956
1994	11.9714673863291
1995	11.914329538272646
1996	12.286652847556478
1997	11.597486289315029
1998	10.546004969845312
1999	10.865948764796403
2000	11.09938445901075
2001	10.83758748893865
2002	11.029718025850384
2003	11.298427120652523
2004	10.862438826564356
2005	10.55784908655118
2006	9.754349650166999
2007	10.127681389276043
2008	10.523629648837964
2009	11.167933484097032
2010	10.533978102811217
2011	10.658423396225102
2012	10.098680961488386
2013	11.006326023733203
2014	11.35192575130736