Year % of total energy 1971 0.18024463288325263 1972 0.054383956052795314 1973 0.33022272253842677 1974 0.11878960265083433 1975 0.12484544744565168 1976 0.1150794954421153 1977 0.009692581856224245 1978 0.008890275041676183 1979 0.028220857601464918 1980 0.03518362061840523 1981 0.03571519780713735 1982 0.032081604156966446 1983 0.01207926031241188 1984 0.04670547440540002 1985 0.04195404474418476 1986 0.038749351351661 1987 0.035610201835719515 1988 0.029170617628966593 1989 0.02497350622892714 1990 0.06460502889496968 1991 0.2186430237457098 1992 0.09171308990149571 1993 0.029903460118150378 1994 0.015295759131228603 1995 0.04476075407369509 1996 0.025283233394215652 1997 0 1998 0 1999 0 2000 0 2001 0 2002 0 2003 0 2004 0 2005 0 2006 0 2007 0 2008 0 2009 0 2010 0 2011 0 2012 0 2013 0 2014 0