Year	% of total fuel combustion
1960	29.78725036193325
1961	29.126523007526167
1962	28.20111920160511
1963	28.209936463113316
1964	28.876935423500818
1965	28.894591547105254
1966	28.788487892650114
1967	29.806666216641272
1968	29.173702005427554
1969	28.47832170704843
1970	26.35727218005789
1971	25.155887877280037
1972	24.433701449767252
1973	24.410938748227007
1974	24.254217064929072
1975	22.37650162702187
1976	21.934730262820842
1977	21.860415186866188
1978	21.014968101827293
1979	21.755695483308557
1980	21.22193990300687
1981	20.795965924442868
1982	19.59373768418023
1983	18.79873895394628
1984	19.071582149037702
1985	18.867899001546487
1986	18.146847072701604
1987	17.99419788273616
1988	17.931780936323097
1989	17.249784734444333
1990	17.151516241591427
1991	16.479929055661863
1992	15.663027229893363
1993	15.101745124078423
1994	14.887111883459822
1995	14.35377380853346
1996	13.927173520057151
1997	13.951159147138707
1998	13.558651587360666
1999	13.398831048909203
2000	13.912368661403216
2001	13.603056862959493
2002	12.966560201437908
2003	12.874576861930809
2004	12.910460800371006
2005	12.17835991018622
2006	12.517421365868053
2007	12.217291195468345
2008	12.033297984264774
2009	11.116311745727748
2010	11.758658483498595
2011	11.959787573486024
2012	11.76019292701466
2013	11.700873744998134
2014	11.900836253598264