Year Percent 1995 16.15 1996 16.29 1997 15.63 1998 16.26 1999 15.91 2000 15.36 2001 16.99 2002 16.06 2003 15.6 2004 14.11 2005 14.07 2006 13.84 2007 11.45 2008 11.24 2009 10.63 2010 10.5