Year Percent 2001-01-01 20.1000 2002-01-01 19.1000 2003-01-01 17.0000 2004-01-01 15.7000 2005-01-01 14.4000 2006-01-01 9.7000 2007-01-01 8.8000 2008-01-01 9.4000 2009-01-01 10.7000 2010-01-01 11.7655 2011-01-01 13.6144 2012-01-01 14.2134 2013-01-01 14.3677 2014-01-01 14.3778 2015-01-01 14.0983 2016-01-01 14.3547