Year % of total fuel combustion 2000 3.131115459882583 2001 3.0864197530864197 2002 3.10077519379845 2003 3.2448377581120944 2004 2.7737226277372264 2005 3.1578947368421053 2006 3.129657228017884 2007 3.125000000000001 2008 4.089709762532982 2009 3.80499405469679 2010 3.6739380022962105 2011 3.82830626450116 2012 3.3210332103321036 2013 3.369434416365824 2014 4.45945945945946