Year	% of total fuel combustion
1960	29.303831227353825
1961	28.667935351300944
1962	27.80438202941965
1963	27.828992142547794
1964	28.45491489708629
1965	28.49392860021915
1966	28.405537225649116
1967	29.401773971639614
1968	28.766279513434462
1969	28.066828421169312
1970	26.037816634743145
1971	25.063820976823806
1972	24.392815545883654
1973	24.36323108979018
1974	24.19565589394043
1975	22.445878487816593
1976	22.014849638230952
1977	21.946682671631983
1978	21.15839077817554
1979	21.865783529007857
1980	21.262460036067598
1981	20.85837191738089
1982	19.65289889487989
1983	18.964547215457447
1984	19.196717498338213
1985	18.966918982235164
1986	18.24253991953561
1987	18.11698298629151
1988	17.98886648637153
1989	17.374923080798446
1990	16.624620207357097
1991	15.85490105174635
1992	14.974402462670446
1993	14.909824308353645
1994	14.859019355674638
1995	14.445580044389187
1996	14.171419677464701
1997	14.130499385838627
1998	13.67709856200081
1999	13.365058834067305
2000	13.96300426505441
2001	13.404895208602095
2002	12.908407799998562
2003	12.807046174221146
2004	12.809484341003136
2005	12.19839827463594
2006	12.510457187456671
2007	12.152099628147596
2008	11.865496550081023
2009	10.946116879622389
2010	11.681241796201737
2011	11.910217919653617
2012	11.634913411851374
2013	11.619842046303825
2014	11.737986750578555