Year	% of total fuel combustion
1971	8.661417322834646
1972	10.212298682284041
1973	9.525471039776692
1974	7.88704965920156
1975	8.059384941675502
1976	7.528314457028648
1977	4.867827208252739
1978	3.0596788851863064
1979	3.1165717710518437
1980	5.574712643678161
1981	3.320927569424563
1982	3.9729501267962806
1983	3.265524625267666
1984	2.804974861074358
1985	2.786926779832785
1986	2.6145418326693233
1987	5.022295235860127
1988	4.271123491179202
1989	4.2159268347089
1990	3.1454783748361725
1991	2.777777777777778
1992	2.426693629929221
1993	2.839056205639747
1994	7.360552041403105
1995	2.4793388429752063
1996	2.777777777777778
1997	2.5967413441955194
1998	2.5615099427030668
1999	2.6148817535089397
2000	2.7136791582056485
2001	2.709134175361523
2002	2.8185107598552652
2003	2.951388888888889
2004	2.5976524918222053
2005	2.445398543961172
2006	2.6654240447343907
2007	2.7027027027027035
2008	3.0924128011506657
2009	4.404540064374047
2010	4.583956153462879
2011	5.153693225263801
2012	5.566630884833616
2013	5.065613094398193
2014	5.655172413793103