Year	% of total fuel combustion
1971	12.080536912751677
1972	11.76470588235294
1973	14.970059880239523
1974	15.760869565217389
1975	13.513513513513512
1976	13.679245283018867
1977	11.877394636015326
1978	11.48936170212766
1979	11.688311688311687
1980	13.812154696132598
1981	13.756613756613758
1982	13.36898395721925
1983	15.816326530612246
1984	17.877094972067038
1985	15.46961325966851
1986	15.962441314553994
1987	17.59259259259259
1988	15.104166666666666
1989	14.619883040935672
1990	17.391304347826086
1991	13.186813186813188
1992	12.264150943396226
1993	11.483253588516746
1994	12.97071129707113
1995	11.15537848605578
1996	10.902255639097742
1997	11.88811188811189
1998	10.11904761904762
1999	11.504424778761061
2000	10.734463276836157
2001	11.590296495956872
2002	13.577023498694519
2003	15.443037974683543
2004	14.878048780487807
2005	16.129032258064516
2006	16.27358490566038
2007	14.449541284403669
2008	14.081145584725535
2009	11.031175059952039
2010	11.682242990654206
2011	11.185682326621924
2012	11.738148984198647
2013	11.971830985915494
2014	12.33480176211454