Year % of energy use 1990 69.27508989484407 1991 71.09563367386484 1992 60.31119750798083 1993 57.628693067610406 1994 66.79299053974825 1995 55.859528041946724 1996 52.238483181656534 1997 54.38360506300225 1998 50.63890400476423 1999 54.060761967595674 2000 52.52181300549748 2001 47.83570343293132 2002 42.107970839621636 2003 40.98034458180428 2004 43.43812239939404 2005 54.266883533038026 2006 58.34514943927937 2007 58.175861424790966 2008 57.69386027271006 2009 49.888463026206345 2010 78.44050318137987 2011 78.99874734250032 2012 78.91510799793082 2013 76.4981837740342 2014 75.04470837028974