Year	% of total fuel combustion
1960	31.081081081081084
1961	32.42736644798501
1962	33.930348258706466
1963	32.13627992633518
1964	33.68146214099217
1965	34.944868532654795
1966	36.01312551271534
1967	36.688851913477535
1968	38.47415914684168
1969	35.60371517027863
1970	35.33236994219653
1971	37.407407407407405
1972	36.39301874595992
1973	34.191616766467064
1974	36.05520414031052
1975	40.10955569080949
1976	36.52365236523652
1977	35.63034188034188
1978	36.95771554091159
1979	41.01466992665036
1980	40.98360655737705
1981	40.98461538461539
1982	37.56967670011148
1983	37.54152823920266
1984	38.77440347071583
1985	38.35978835978836
1986	42.002237136465325
1987	40.51228437009932
1988	40.4703576678099
1989	42.71797369702873
1990	39.83440662373505
1991	39.25657298277426
1992	37.98319327731092
1993	40.30742954739539
1994	42.580101180438454
1995	45.04805683242791
1996	43.74498797113071
1997	40.94922737306844
1998	42.343691501310374
1999	41.230878690857345
2000	41.73282706247843
2001	38.97978825794033
2002	40.63706563706564
2003	39.91507430997877
2004	41.504779525131056
2005	40.14836795252225
2006	40.52132701421801
2007	42.34897270775836
2008	41.52466367713004
2009	44.71437951411687
2010	44.81054365733113
2011	46.003372681281625
2012	43.383530919577055
2013	44.218346253229974
2014	44.94238156209987