Year % of total fuel combustion 1971 0 1972 0 1973 0 1974 0 1975 0 1976 0 1977 0 1978 0 1979 0 1980 1.6241299303944332 1981 3.041825095057035 1982 2.6711185308848084 1983 2.4502297090352223 1984 2.1186440677966103 1985 2.2757697456492645 1986 1.0922330097087378 1987 0.23041474654377903 1988 0.35671819262782434 1989 0 1990 6.989247311827955 1991 7.717041800643086 1992 7.98514391829155 1993 8.073394495412844 1994 5.372616984402079 1995 7.585644371941274 1996 1.9762845849802364 1997 2.1903323262839893 1998 1.965065502183404 1999 1.9622093023255829 2000 2.2869022869022873 2001 2.2377622377622366 2002 2.17391304347826 2003 2.4016010673782535 2004 2.2565320665083135 2005 2.2087244616234125 2006 2.27027027027027 2007 2.4831867563373002 2008 2.252010723860591 2009 2.162718846549948 2010 2.118644067796611 2011 2.3080782739588557 2012 2.1510096575943813 2013 1.0685663401602847 2014 1.9908751555371216