Year % 2001 14.8 2002 13.3 2003 10.2 2004 8.3 2005 7.5 2006 3.9 2007 2.4 2008 2.3 2009 1.3 2010 1.1 2011 0.9 2012 0.5 2013 0.4 2014 0.4 2015 0.3