Year Percent 1996-01-01 40.2632 1997-01-01 44.2396 1998-01-01 45.0734 1999-01-01 45.5508 2000-01-01 44.4668 2001-01-01 45.3586 2002-01-01 47.4138 2003-01-01 46.9345 2004-01-01 47.6079 2005-01-01 41.0382 2006-01-01 40.0117 2007-01-01 42.9611 2008-01-01 48.4214 2009-01-01 46.2205 2010-01-01 43.4560 2011-01-01 43.0073 2012-01-01 49.7502 2013-01-01 41.6216 2014-01-01 39.0885