Year Percent 2000 15.8155 2001 18.8612 2002 17.3609 2003 13.1947 2004 11.6235 2005 9.8353 2006 9.2963 2007 7.2863 2008 5.7579 2009 6.6244 2010 9.6078 2011 10.1075 2012 10.8404 2013 11.8446 2014 10.4043 2015 8.417 2016 6.9685 2017 5.9459