Year % of total fuel combustion 1971 40.83414161008729 1972 44.56048738033072 1973 40.50847457627118 1974 36.349453978159126 1975 33.93432066967161 1976 34.439834024896264 1977 33.41596430342092 1978 34.96257155438133 1979 35.55806938159879 1980 31.45253526496378 1981 24.87128712871287 1982 19.91899852724595 1983 30.082855321861057 1984 31.7643576080521 1985 32.79768177028451 1986 37.00824499411071 1987 34.56818181818182 1988 35.53031839383492 1989 34.680382072005884 1990 31.799961824775718 1991 32.85681346552917 1992 44.67540292212683 1993 52.982695810564664 1994 56.57894736842105 1995 56.44313643052343 1996 54.25815719269445 1997 61.58157456870128 1998 47.916140439504915 1999 30.9903103957957 2000 35.37173666288309 2001 39.42187889359581 2002 38.03754493409666 2003 46.3274399885008 2004 42.35520175679385 2005 37.62132604237867 2006 36.499419953596295 2007 28.260521683469353 2008 39.54130975407571 2009 53.49722615033177 2010 55.492222973625736 2011 50.974377481053764 2012 50.20986774372377 2013 54.71628319893469 2014 65.04289867404098