Year	% of total fuel combustion
1971	76.7123287671233
1972	80.51948051948051
1973	80
1974	77.49999999999999
1975	73.52941176470587
1976	75.26881720430106
1977	75.93984962406014
1978	72.02797202797203
1979	72.07792207792208
1980	70.65868263473054
1981	68
1982	69.68085106382979
1983	74.01960784313727
1984	73.83177570093457
1985	73.109243697479
1986	71.73913043478261
1987	73.24561403508773
1988	74.69879518072288
1989	67.27941176470587
1990	66.28787878787878
1991	64.60905349794238
1992	69.16299559471366
1993	69.83471074380165
1994	69.01960784313727
1995	69.51219512195121
1996	70.90163934426229
1997	70.8171206225681
1998	70.14925373134328
1999	68.33333333333333
2000	66.66666666666667
2001	68.63468634686348
2002	71.0344827586207
2003	70.46979865771812
2004	71.7607973421927
2005	72.0136518771331
2006	60.12861736334406
2007	51.69902912621359
2008	51.053864168618276
2009	52.18295218295218
2010	52.87128712871287
2011	54.83234714003944
2012	54.49438202247191
2013	52.478632478632484
2014	53.807947019867555