Year	% of total fuel combustion
1960	13.784973278843129
1961	13.354427201044647
1962	13.22595926101374
1963	13.386121913507942
1964	12.686095822430751
1965	11.891797708759857
1966	11.796223847593128
1967	11.494819930932412
1968	11.35118085399992
1969	10.555738243998684
1970	10.343719884355925
1971	9.823572397953857
1972	9.78003271137221
1973	9.48849104859335
1974	9.162746364111552
1975	9.158773715735741
1976	8.336781704322878
1977	8.172025809203861
1978	7.654246945048354
1979	7.1873538029694926
1980	6.759452897766881
1981	6.757212099219823
1982	6.10437667474799
1983	6.398579221108715
1984	6.089227314882608
1985	5.728624183315974
1986	5.812297130046938
1987	5.681382822887792
1988	5.561974304464369
1989	5.759744656156301
1990	5.8637589536873245
1991	6.090271160010396
1992	6.353762836258174
1993	6.163150907213454
1994	6.464779855337794
1995	6.691460963978284
1996	7.236955152070565
1997	7.912178956089479
1998	9.027711036360724
1999	10.123155149073861
2000	9.307463923220327
2001	9.279207509265353
2002	9.15555241093855
2003	9.648703956343793
2004	10.80680478356072
2005	11.63810551882337
2006	12.405941878567722
2007	13.802440138318001
2008	14.66922974943656
2009	15.319455399705067
2010	15.309838090903183
2011	15.73445023415342
2012	15.462422873326817
2013	14.77677348671597
2014	15.668004587155963