Year Percent 1995 17.84 1996 18.41 1997 18.45 1998 19.42 1999 20.62 2000 20.44 2001 20.22 2002 18.13 2003 14.95 2004 14.71 2005 14.4 2006 13.79 2007 13.64 2008 13.64 2009 13.64 2010 13.64