Year Percent 1995-01-01 47 1996-01-01 53 1997-01-01 56 1998-01-01 60 1999-01-01 67 2000-01-01 67 2001-01-01 67 2002-01-01 71 2003-01-01 71 2004-01-01 71 2005-01-01 71 2006-01-01 79 2007-01-01 79 2008-01-01 76 2009-01-01 83 2010-01-01 83 2011-01-01 79 2012-01-01 83 2013-01-01 83