Year	% of total fuel combustion
1960	23.07692307692308
1961	24.347826086956527
1962	21.7741935483871
1963	22.047244094488192
1964	21.70542635658915
1965	23.571428571428573
1966	21.333333333333336
1967	22.535211267605636
1968	19.463087248322147
1969	21.05263157894737
1970	21.969696969696965
1971	22.142857142857146
1972	21.333333333333336
1973	22.754491017964074
1974	21.08433734939759
1975	23.60248447204969
1976	25.78616352201258
1977	25.153374233128833
1978	26.136363636363637
1979	27.322404371584696
1980	26.857142857142858
1981	32.758620689655174
1982	31.41025641025641
1983	30.18867924528302
1984	30.76923076923077
1985	30.67484662576687
1986	30.58823529411765
1987	33.33333333333333
1988	32.240437158469945
1989	32.967032967032964
1990	33.15789473684211
1991	34.22459893048128
1992	33.15789473684211
1993	32.47422680412371
1994	32.19512195121952
1995	31.122448979591837
1996	30.493273542600903
1997	27.96208530805687
1998	29.047619047619044
1999	30.243902439024396
2000	29.166666666666664
2001	30.476190476190474
2002	29.09090909090909
2003	29.22374429223745
2004	29.515418502202646
2005	30.04484304932736
2006	39.647577092511014
2007	41.810344827586206
2008	42.924528301886795
2009	42.78846153846153
2010	43.07692307692307
2011	43.85026737967914
2012	43.01075268817204
2013	39.90147783251232
2014	40.19607843137255