Year Percent 1995-01-01 41 1996-01-01 41 1997-01-01 42 1998-01-01 40 1999-01-01 45 2000-01-01 45 2001-01-01 42 2002-01-01 42 2003-01-01 42 2004-01-01 38 2005-01-01 39 2006-01-01 39 2007-01-01 45 2008-01-01 45 2009-01-01 43 2010-01-01 43 2011-01-01 41 2012-01-01 41 2013-01-01 41