Year % 2002 15.67 2003 15.21 2004 12.51 2005 15.09 2006 15.77 2007 14.75 2008 13.89 2009 14.25 2010 13.93 2011 12.9 2012 12.21 2013 11.83 2014 12.47 2015 11.71 2016 11.19 2020 10.33