Year Percent 1996-01-01 25.32560 1997-01-01 25.45050 1998-01-01 23.60530 1999-01-01 22.83150 2000-01-01 26.46690 2001-01-01 33.48210 2002-01-01 42.44660 2003-01-01 48.05000 2004-01-01 7.93283 2005-01-01 23.59120 2006-01-01 33.46090 2007-01-01 16.36400 2008-01-01 17.74530 2009-01-01 18.77030 2010-01-01 27.86920 2011-01-01 33.33920 2012-01-01 36.41380 2013-01-01 37.57750 2014-01-01 31.85320