Year	% of total fuel combustion
1960	9.67054945461953
1961	9.992867462828508
1962	9.991217647362712
1963	9.885931558935363
1964	10.035088828475692
1965	9.984626968689213
1966	10.642615197801495
1967	10.552520125440497
1968	10.4016273094335
1969	10.080582783692183
1970	9.589766570252984
1971	10.199450004600333
1972	10.36021644935205
1973	10.13846782547542
1974	9.96832204298455
1975	10.886023935487184
1976	10.44358520994035
1977	11.189273451991003
1978	11.652359086976775
1979	11.484298242422037
1980	12.253307515476408
1981	12.238471076820122
1982	12.788001887527953
1983	12.9804688700212
1984	13.093242035722533
1985	12.999462461924386
1986	13.551615273117172
1987	14.19061177838824
1988	14.797304805487366
1989	15.519971845856062
1990	16.865368457996112
1991	17.590211801621194
1992	18.687127607459814
1993	19.34033671269324
1994	19.319848234445196
1995	19.597520690097934
1996	19.05202051513273
1997	19.856140350877194
1998	20.397634030294803
1999	21.794289780744265
2000	21.347858197932055
2001	20.38313070457087
2002	20.426400655248713
2003	19.97953316115199
2004	20.372027137851337
2005	19.77604352026031
2006	19.1992492962152
2007	19.344826686836544
2008	19.201052536535663
2009	20.410656522885983
2010	19.51322360878675
2011	20.49746345598994
2012	19.934745830983648
2013	19.94082685308826
2014	21.365465178978805