Year Percent 1993 18.86472 1994 16.75561 1995 16.33909 1996 15.38786 1997 15.17936 1998 14.43578 1999 14.94013 2000 14.51694 2001 14.80355 2002 14.61555 2003 15.0555 2004 15.4908 2005 14.36542 2006 14.08293 2007 14.50234 2008 13.44186 2009 13.36082 2010 13.44956 2011 14.31396 2012 14.68783 2013 14.94643 2014 14.17156 2015 14.55582 2016 14.65864