Year Percent 1996-01-01 53.5449 1997-01-01 53.8866 1998-01-01 66.4906 1999-01-01 60.3733 2000-01-01 65.7391 2001-01-01 66.3998 2002-01-01 67.6578 2003-01-01 67.2726 2004-01-01 68.7384 2005-01-01 72.9529 2006-01-01 72.1364 2007-01-01 72.3659 2008-01-01 72.8542 2009-01-01 76.6518 2010-01-01 78.1411 2011-01-01 78.6005 2012-01-01 77.3276 2013-01-01 73.3997 2014-01-01 73.9195 2015-01-01 69.0556 2016-01-01 66.9415