Year Percent 1995 16.66 1996 16.46 1997 20.11 1998 17.89 1999 20.08 2000 18.95 2001 18.25 2002 19.35 2003 19 2004 18.54 2005 18.57 2006 18.33 2007 18.27 2008 13.36 2009 15.71 2010 14.74