Year Percent 1995 17.83 1996 17.83 1997 17.83 1998 16.98 1999 16.64 2000 16.72 2001 15.73 2002 15.76 2003 15.48 2004 15.62 2005 15.65 2006 15.4 2007 15.02 2008 14.94 2009 15.14 2010 15.33