Year Percent 1999 9.18454 2000 10.73111 2001 10.91552 2002 8.87882 2003 8.94125 2004 8.56083 2005 8.86073 2006 8.40398 2007 7.51554 2008 7.98386 2009 10.42612 2010 10.47916 2011 10.00504 2012 11.35661 2013 11.48752 2014 12.81095 2015 13.02287 2016 12.53606