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	16.086162680492837
1972	15.863141524105755
1973	15.393934176218824
1974	15.02557468877206
1975	15.339160801933497
1976	14.9319988700109
1977	15.05399727931446
1978	14.650647580095434
1979	14.491072538216168
1980	13.818776626865427
1981	14.139906323377625
1982	14.234570069287011
1983	14.48314436533554
1984	14.418952436533411
1985	15.23679112711642
1986	14.888450134492741
1987	14.772532494202949
1988	14.956058572187734
1989	14.382377665431383
1990	13.214684200682356
1991	12.72993101073184
1992	11.384527279962985
1993	11.533319621554917
1994	10.894057520467454
1995	10.538318896853843
1996	9.52020904845842
1997	10.025083547508236
1998	8.84870681184215
1999	9.395061440891766
2000	8.879043658797714
2001	8.67560680815104
2002	8.25607843515899
2003	7.983211834495743
2004	7.781557686512524
2005	7.395873922215863
2006	7.185162187228707
2007	7.041855124936588
2008	7.103826122734771
2009	6.782668721590633
2010	6.3623093366212045
2011	6.227464857358638
2012	6.232360607604038
2013	6.129213189265848
2014	6.232441565674858