Year	% of total fuel combustion
1971	29.368956235669422
1972	31.11447779566329
1973	30.748482805124745
1974	32.604166666666664
1975	34.792359446291854
1976	35.81669946584201
1977	37.329682073203315
1978	38.28529644750473
1979	35.97707423580786
1980	35.90888789638232
1981	37.07543970153593
1982	37.507547958567514
1983	36.6103045325779
1984	35.61453121601045
1985	35.36894598935001
1986	34.42912254781253
1987	33.85277589573951
1988	34.118546845124285
1989	33.35997674756576
1990	29.510457366122733
1991	29.755661845214085
1992	30.893126782618413
1993	29.801857917628745
1994	28.708070933572237
1995	29.287174246295347
1996	29.523880154256894
1997	28.040742959856207
1998	29.931226951061497
1999	31.971976753443194
2000	31.63757069092697
2001	32.06306886089914
2002	32.36019831661478
2003	31.314902532337403
2004	32.564351627003404
2005	32.91773164599048
2006	32.424171672362185
2007	33.22307575131112
2008	31.262143467785805
2009	31.52421436162137
2010	31.55313158500522
2011	31.849737593223455
2012	32.16432350976934
2013	31.334174366667806
2014	31.212476941137012