Year	% of total fuel combustion
1971	49.08424908424907
1972	48.69791666666667
1973	47.630057803468205
1974	47.460404150737304
1975	47.56446991404011
1976	48.47622917513206
1977	52.648193616274995
1978	52.49249249249249
1979	52.24465200361555
1980	52.27394328517924
1981	49.877390877881325
1982	48.60486048604861
1983	47.86906854130053
1984	47.36965162497077
1985	45.03697064754649
1986	45.79069767441861
1987	43.88850811057802
1988	45.179002855260265
1989	45.73660229984812
1990	45.674740484429066
1991	48.2766288636869
1992	48.56592877767084
1993	46.278449866721346
1994	44.355575868372945
1995	46.871663463591716
1996	47.648067034850506
1997	51.14698385726424
1998	46.45573997233748
1999	46.602409638554214
2000	47.58890898131404
2001	49.8423577793009
2002	50.438653921697
2003	51.119023397761964
2004	52.26244343891402
2005	48.953068592057754
2006	46.14028459891701
2007	44.46550416982563
2008	47.11729622266402
2009	51.82881313759642
2010	48.836721861245024
2011	44.274432379072046
2012	43.87933413041479
2013	43.38820549927641
2014	41.967598877726495