Year Percent 1995 15.17 1996 15.15 1997 15.07 1998 15.29 1999 15.34 2000 15.49 2001 15.69 2002 15.91 2003 16.16 2004 16.33 2005 16.41 2006 16.49 2007 16.49 2008 16.32 2009 16.34 2010 16.34