Year	% of total fuel combustion
1960	26.73182178785475
1961	27.137904340979617
1962	27.526809460260505
1963	28.347851898519476
1964	28.382876798254188
1965	29.380328850354243
1966	29.989440615281165
1967	28.431560711742335
1968	29.46280607463822
1969	30.713748334863304
1970	31.739286700474683
1971	32.294349471937494
1972	33.47185771430677
1973	34.611360504735856
1974	34.91516474590039
1975	35.24133558748944
1976	35.555386834712614
1977	36.606338246957364
1978	36.24127472603945
1979	36.45192147330525
1980	37.92589344442008
1981	38.62332347339844
1982	39.142029626072315
1983	40.25924277313154
1984	40.10186096081325
1985	40.65443223174514
1986	40.63572487564542
1987	41.21946903006814
1988	41.23642258643796
1989	42.56905136905586
1990	44.001018772608816
1991	44.77467821519269
1992	46.03095281073943
1993	46.002340347554636
1994	45.81769446814432
1995	46.550490846762735
1996	46.59417489372168
1997	47.6922474629701
1998	48.23733214906825
1999	47.561701188094446
2000	47.147906819661586
2001	47.60690457224268
2002	47.341575485107924
2003	47.36836108348486
2004	47.20987980154138
2005	47.98015182729846
2006	47.66919478009331
2007	48.136043959564894
2008	48.46633974567552
2009	47.7838091146952
2010	47.997922661717375
2011	47.35031521287092
2012	46.21483536711293
2013	45.922934312664076
2014	45.287479868295456