Year % of total energy use 2000 0 2001 0 2002 0 2003 0 2004 0 2005 0.009922454861483682 2006 0.009675439627788088 2007 0.009247724495232852 2008 0.013248392990470401 2009 0.012496615499968756 2010 0.011577231803104493 2011 0 2012 0 2013 0.01199574290612215 2014 0.011918414296553706