Year Percent 1995 13.72 1996 13.93 1997 12.79 1998 14.06 1999 14.57 2000 14.93 2001 15.28 2002 16.01 2003 15.43 2004 15.38 2005 15.57 2006 15.8 2007 18.48 2008 20.78 2009 15.86 2010 14.28