Year Percent 1995-01-01 29 1996-01-01 35 1997-01-01 40 1998-01-01 41 1999-01-01 40 2000-01-01 44 2001-01-01 42 2002-01-01 49 2003-01-01 49 2004-01-01 46 2005-01-01 43 2006-01-01 41 2007-01-01 39 2008-01-01 40 2009-01-01 39 2010-01-01 39 2011-01-01 40 2012-01-01 40 2013-01-01 37