Year	% of total fuel combustion
1971	8.985377832347359
1972	9.490238611713666
1973	10.219284440247614
1974	10.400639424517935
1975	10.451977401129945
1976	10.10715583000363
1977	10.141040062299904
1978	11.25393929341516
1979	11.27417259038447
1980	11.934245781736548
1981	11.482313307130822
1982	11.04589114194237
1983	10.886283408976297
1984	9.960281087687138
1985	10.494788546783276
1986	10.224064395987266
1987	10.831095923846718
1988	11.496977598672515
1989	12.470841557509424
1990	14.064961822809355
1991	14.387464387464387
1992	15.162257976547586
1993	14.835687623508743
1994	15.63876651982379
1995	15.902589872439115
1996	17.339494163424124
1997	17.119455032033088
1998	18.54070912672357
1999	15.65407772304324
2000	16.404977040438453
2001	16.254766275949724
2002	17.02654867256637
2003	16.729182295573892
2004	18.243729945648614
2005	18.86602814236727
2006	18.934709853082985
2007	20.454545454545457
2008	20.27333591545399
2009	21.770295049174862
2010	22.31830937517897
2011	25.974374454954045
2012	25.901016156151762
2013	31.516472868217054
2014	30.791094268119377