Year	% of total fuel combustion
1971	33.74635568513119
1972	36.301134410450324
1973	35.33614810003248
1974	35.501269035533
1975	34.46682073291515
1976	33.45081704581865
1977	32.84203780839474
1978	35.60675883256529
1979	35.70159857904085
1980	36.0248447204969
1981	35.75403450194769
1982	37.09182249511582
1983	36.9937483011688
1984	36.45776566757493
1985	36.53797628059551
1986	36.63030303030304
1987	34.72188189169321
1988	36.332417582417584
1989	35.99909379247847
1990	38.351409978308034
1991	39.89876760563379
1992	39.76759199483537
1993	37.09011943539631
1994	37.8372935964559
1995	36.25730994152047
1996	36.77270479643976
1997	34.97723823975721
1998	36.12184249628529
1999	33.38374810944589
2000	33.81454025230849
2001	33.607730851825345
2002	34.149104917289826
2003	34.58816288850139
2004	35.27199074074074
2005	35.176017601760186
2006	34.55089820359282
2007	34.60801532811752
2008	34.56752884397858
2009	36.845417045375086
2010	36.76778242677825
2011	38.108484005563284
2012	37.08444444444444
2013	37.452153754919415
2014	37.820641282565134