Year Percent 2001 8.71469 2002 10.39245 2003 10.21232 2004 10.33047 2005 10.20985 2006 14.2807 2007 16.11015 2008 13.71916 2009 12.48725 2010 11.98268 2011 12.45402 2012 10.57483 2013 7.82534 2014 7.83843 2015 7.64531