Year Percent 1996-01-01 41.9820 1997-01-01 45.1612 1998-01-01 45.9885 1999-01-01 37.5956 2000-01-01 41.0711 2001-01-01 44.6704 2002-01-01 45.8239 2003-01-01 47.2798 2004-01-01 43.1087 2005-01-01 40.8296 2006-01-01 39.0041 2007-01-01 35.2183 2008-01-01 29.9089 2009-01-01 44.1004 2010-01-01 42.9576 2011-01-01 35.6307 2012-01-01 42.3686 2013-01-01 51.5692 2014-01-01 44.6752