Year	% of total fuel combustion
1960	24.8062015503876
1961	23.705057891529556
1962	23.20561252023745
1963	27.057663873829473
1964	24.415467625899282
1965	22.396274343776458
1966	20.954128440366972
1967	23.225152129817445
1968	24.239573534023208
1969	23.603192702394526
1970	23.37798791699501
1971	15.351012571476403
1972	15.189966801918112
1973	14.80993636717808
1974	14.446337156809985
1975	14.760568144750456
1976	14.509653185570269
1977	14.641279694401335
1978	14.414423262650967
1979	14.364264191611499
1980	13.77552283899407
1981	14.01602161366188
1982	13.977764973251865
1983	14.208659900504227
1984	14.254013870919849
1985	14.634838489976087
1986	14.164574106295476
1987	14.025241200934104
1988	14.158945149174404
1989	13.877748053130091
1990	12.376788553259138
1991	11.97016878066705
1992	11.23998139891129
1993	11.46511186054244
1994	11.264636636448966
1995	11.346376943233048
1996	10.77345005579879
1997	11.132719250820838
1998	10.176330778363614
1999	10.621514378068932
2000	10.215301072503086
2001	9.977378493521554
2002	9.709700631267575
2003	9.35715843036684
2004	9.119536144378632
2005	8.69356529312711
2006	8.48455942480388
2007	8.248759951299146
2008	8.167205584743652
2009	7.817509051709569
2010	7.3607431563504395
2011	7.237706325776564
2012	7.133796154863886
2013	7.052425540568618
2014	7.0530943179175365