Year Percent 1995-01-01 19 1996-01-01 21 1997-01-01 32 1998-01-01 35 1999-01-01 42 2000-01-01 53 2001-01-01 53 2002-01-01 59 2003-01-01 67 2004-01-01 67 2005-01-01 70 2006-01-01 81 2007-01-01 81 2008-01-01 81 2009-01-01 79 2010-01-01 79 2011-01-01 79 2012-01-01 82 2013-01-01 82