Year Percent 1995 12.39 1996 15.7 1997 17.45 1998 16.89 1999 19.54 2000 21.36 2001 19.65 2002 19.5 2003 18.82 2004 18.27 2005 16.06 2006 16.98 2007 20.33 2008 18.62 2009 18.3 2010 23.44