Year	% of total fuel combustion
1960	19.540372891598388
1961	19.804057299465995
1962	19.960343688037014
1963	19.009301375592077
1964	18.33900829963822
1965	18.13370896604713
1966	17.921213659306883
1967	18.005396542738012
1968	17.456688630252273
1969	17.52108489689764
1970	19.022318442554177
1971	19.061400297101972
1972	18.39058623942178
1973	17.048219102141765
1974	16.68741283853897
1975	17.031575418429977
1976	17.26467988491802
1977	16.128701625504373
1978	16.10599247403122
1979	14.846802171127338
1980	13.948417059672288
1981	13.182340600603121
1982	13.757522451624851
1983	13.367894230612478
1984	13.308657941091218
1985	12.713879011443069
1986	12.48216052512267
1987	12.291143175400876
1988	12.478182648156602
1989	12.341935418089868
1990	11.35462107882435
1991	11.64748224085286
1992	11.678485042690866
1993	11.82131916552068
1994	11.459921726632455
1995	11.43010892576254
1996	11.782331187927602
1997	11.116011370248344
1998	10.127645900815885
1999	10.429247052420216
2000	10.614357818326175
2001	10.374584756134547
2002	10.525574211729003
2003	10.795368447324554
2004	10.374837371215582
2005	10.02688403039491
2006	9.236012182103162
2007	9.652541568030164
2008	10.089048229014336
2009	10.765703035428634
2010	10.190291843165857
2011	10.230125041258242
2012	9.712099378881987
2013	10.679440426244865
2014	11.011917986325903