Year Percent 1995 19.92 1996 22.88 1997 24.57 1998 24.89 1999 23.15 2000 21.41 2001 18.55 2002 18.98 2003 20.51 2004 19.8 2005 18.98 2006 18.81 2007 18.81 2008 18.81 2009 19.31 2010 20.15