Year	% of total fuel combustion
1971	26.328895699645628
1972	25.579399141630898
1973	24.011189680627865
1974	25.224664731093604
1975	24.844227244960294
1976	24.85308259429426
1977	24.23547773496561
1978	23.303711931870776
1979	23.99901944762216
1980	22.27619429947812
1981	22.313704659280614
1982	22.41746173381838
1983	20.793030940222287
1984	20.70004505519261
1985	20.637163423087173
1986	19.4207702020202
1987	20.589482083634643
1988	20.206967754327835
1989	20.625956259562596
1990	20.241625959525468
1991	20.74035453597497
1992	19.647634334632727
1993	17.383164110319004
1994	16.149888068428616
1995	16.556409797961738
1996	15.609686923913216
1997	15.515763968915282
1998	15.251735054182392
1999	15.80792817112174
2000	15.162623489115974
2001	15.45804567180032
2002	14.702166064981949
2003	14.41277338793764
2004	13.589046896503053
2005	14.559441168150068
2006	14.481983388496845
2007	15.983680146838775
2008	15.612576103866173
2009	14.170929689859344
2010	14.71151587430657
2011	14.61105653299991
2012	14.27139672720361
2013	13.8203448509945
2014	13.598906752940982