Year Percent 1996-01-01 28.9071 1997-01-01 32.9405 1998-01-01 45.0331 1999-01-01 63.1241 2000-01-01 55.0724 2001-01-01 56.1389 2002-01-01 54.2207 2003-01-01 51.3177 2004-01-01 47.2572 2005-01-01 42.8416 2006-01-01 42.3698 2007-01-01 42.3483 2008-01-01 42.9648 2009-01-01 44.1135 2010-01-01 42.3148 2011-01-01 41.3665 2012-01-01 40.6038 2013-01-01 38.4077 2014-01-01 40.3356 2015-01-01 39.7019 2016-01-01 39.8376