Year % of energy use 1990 98.07050022962976 1991 98.1804916179142 1992 93.30849753679674 1993 82.51092115333218 1994 77.06829039703922 1995 84.31898208642853 1996 57.65076780550798 1997 70.37275550974657 1998 70.49797841782389 1999 64.1211544062544 2000 68.07252059962275 2001 69.58601417428436 2002 60.18360905958181 2003 64.51256979926984 2004 63.81404985308544 2005 65.4283630828704 2006 66.45050594272627 2007 70.78468308489137 2008 73.21742609773611 2009 68.10664490396441 2010 64.65123040784859 2011 67.34421675318019 2012 72.70666159921605 2013 72.0464797313162 2014 71.3413045219602