Year % of total energy use 2000 0.2301543730395854 2001 0.18822916020306318 2002 0.1891127294619658 2003 0.1808528813953815 2004 0.35817672571823356 2005 0.36169601508098886 2006 0.3386941325936391 2007 0.3038038430670196 2008 0.242909114218788 2009 0.342892770845777 2010 0.4393427720436426 2011 0.29190683510895005 2012 0.2734545394656829 2013 0.3835204842325386 2014 0.5191763785084782