Year Percent 1995 38.23 1996 37.85 1997 37.76 1998 35.53 1999 35 2000 35.62 2001 33.6 2002 33.56 2003 25.42 2004 20.36 2005 21.73 2006 20.76 2007 25.01 2008 25.12 2009 22.53 2010 23.77