Year	% of total fuel combustion
1971	77.50865051903114
1972	75.75757575757575
1973	61.124121779859486
1974	52.87128712871287
1975	51.242829827915855
1976	52.464788732394375
1977	55.3968253968254
1978	56.43712574850299
1979	58.82352941176471
1980	62.01657458563537
1981	60.05154639175259
1982	57.125307125307124
1983	58.51063829787233
1984	89.14549653579678
1985	89.34065934065933
1986	90.37871033776868
1987	89.91683991683993
1988	89.9209486166008
1989	89.5711500974659
1990	89.04494382022472
1991	88.52140077821012
1992	89.32676518883417
1993	89.66846569005395
1994	89.60843373493977
1995	89.29368029739777
1996	89.3541518807665
1997	88.56345885634587
1998	88.32684824902725
1999	88.9538661468486
2000	88.69949494949495
2001	88.31804281345566
2002	87.6672484002327
2003	87.31843575418996
2004	85.99550056242968
2005	85.89494163424125
2006	86.57718120805367
2007	85.7830271216098
2008	85.53433563592037
2009	85.36984062116878
2010	84.02505873140173
2011	84.47399296050058
2012	85.28171713300115
2013	81.22347949080621
2014	80.46480296396092