Year	% of total fuel combustion
1971	42.01596806387226
1972	42.52108300044385
1973	39.34267762203964
1974	41.41759180187873
1975	44.9745795854517
1976	45.57640750670241
1977	42.51328540168803
1978	39.98178506375228
1979	38.88277380297193
1980	37.41713724527376
1981	36.51576914825145
1982	36.09455701231625
1983	33.77154023805294
1984	33.50064766839378
1985	32.41272304111714
1986	30.01370488807675
1987	35.10382822432547
1988	33.9441899208663
1989	34.87328405491024
1990	34.15135551843762
1991	31.296128447494496
1992	32.20931684775821
1993	34.257788637751986
1994	27.010148321623735
1995	28.401714635639923
1996	29.642525533890435
1997	28.96914973664409
1998	25.482192060414327
1999	25.889366692728693
2000	24.992478186741554
2001	29.164047768698925
2002	26.964901423393155
2003	24.092999489013796
2004	18.225101467374337
2005	22.638639192366202
2006	22.559652928416487
2007	23.98508192712154
2008	21.305238513315775
2009	18.093217909763226
2010	17.743764172335602
2011	17.35654840122646
2012	14.559670347086481
2013	15.125185777981024
2014	15.184394297916546