Year Percent 1996-01-01 51.3177 1997-01-01 48.0199 1998-01-01 44.7646 1999-01-01 43.8157 2000-01-01 45.0604 2001-01-01 44.7840 2002-01-01 44.9205 2003-01-01 45.7292 2004-01-01 46.2433 2005-01-01 44.8318 2006-01-01 44.0245 2007-01-01 44.3471 2008-01-01 43.7305 2009-01-01 41.1143 2010-01-01 40.2190 2011-01-01 41.1122 2012-01-01 41.7007 2013-01-01 41.1671 2014-01-01 40.4244 2015-01-01 38.7059 2016-01-01 35.3842