Year Percent 1995 15.99 1996 16.26 1997 16.89 1998 16.28 1999 16.38 2000 15.91 2001 15.23 2002 15.2 2003 14.53 2004 14.67 2005 14.62 2006 14.96 2007 14.75 2008 14.61 2009 14.57 2010 14.65