Year Percent 1995 20.86 1996 21.71 1997 20.27 1998 21.37 1999 20.95 2000 21.67 2001 21.36 2002 22.22 2003 22.78 2004 23.13 2005 20.99 2006 22.06 2007 24.63 2008 26.09 2009 30.61 2010 28.99