Year Percent 2000 6.5312 2001 8.0609 2002 8.2951 2003 9.8815 2004 8.2508 2005 8.3632 2006 8.3155 2007 7.8955 2008 6.777 2009 7.629 2010 7.1316 2011 7.1266 2012 7.3145 2013 6.2533 2014 5.3298 2015 5.1999 2016 5.2061 2017 4.6582