Year	% of total fuel combustion
1960	12.555164448883746
1961	12.936450376286862
1962	12.718230968666768
1963	12.648170130239247
1964	12.738329778400116
1965	12.673546258249283
1966	13.161716580625924
1967	13.274117468046256
1968	13.315422748852864
1969	12.920026598168505
1970	12.622672835020177
1971	12.42360119297656
1972	12.71780206311919
1973	12.813625275874086
1974	12.758054870484502
1975	13.547859878863932
1976	13.35669346257579
1977	13.829488637174542
1978	14.044337180380522
1979	13.924647794865404
1980	14.276207768686511
1981	14.598829476559683
1982	15.045190027668362
1983	15.397550730989115
1984	15.751357284255505
1985	15.626963662759202
1986	16.21714098338842
1987	16.680735123778973
1988	17.732103284457065
1989	18.447119546883883
1990	15.751959267145422
1991	16.143836795778522
1992	16.74273162191772
1993	16.985486114943463
1994	17.361787655929703
1995	17.47969179540791
1996	17.734138833236575
1997	18.36632802642766
1998	19.26468003515219
1999	19.656826003207687
2000	19.404625725312258
2001	19.549718455472966
2002	19.848931711064115
2003	19.64812259033976
2004	20.294011696085718
2005	20.416768657371275
2006	20.499492766441247
2007	20.96591795056566
2008	20.991548679424177
2009	21.762423216675916
2010	21.073261399036205
2011	21.051407083133515
2012	20.71955010093889
2013	21.247227377110992
2014	22.360934983034575