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	12.71456892800155
1972	12.6177665781289
1973	12.339133825900904
1974	11.991046579575505
1975	12.128595914207626
1976	12.25469494695292
1977	12.068585964826454
1978	12.16366820569973
1979	11.91899852724595
1980	11.340248819657441
1981	11.175623426836545
1982	11.10583417113322
1983	11.430390972342083
1984	11.756041426927503
1985	11.487509462528386
1986	10.841164706135352
1987	10.79639868273966
1988	10.892908636810182
1989	11.05574442322917
1990	10.41037432933524
1991	10.284988489322854
1992	10.460604471049262
1993	10.284052019164955
1994	10.657828180104207
1995	11.665562421407035
1996	11.505424225410284
1997	11.527919732112988
1998	11.22045376377243
1999	11.226186203431197
2000	11.128641382408235
2001	10.849357243167333
2002	11.000298565315093
2003	10.824317479038614
2004	10.74200551434229
2005	10.558877130159543
2006	10.460606877891435
2007	10.535274622181982
2008	10.184850224525585
2009	9.724633991572214
2010	9.059726285742478
2011	9.179413627919226
2012	9.021279492219074
2013	8.812533111329753
2014	8.449106709041235