Year Percent 1996-01-01 61.5330 1997-01-01 61.5291 1998-01-01 71.0223 1999-01-01 58.6755 2000-01-01 54.7926 2001-01-01 63.2863 2002-01-01 61.7646 2003-01-01 60.0637 2004-01-01 56.5480 2005-01-01 56.7745 2006-01-01 59.1538 2007-01-01 56.3251 2008-01-01 55.0544 2009-01-01 51.5949 2010-01-01 51.0172 2011-01-01 50.7602 2012-01-01 53.3573 2013-01-01 55.8047 2014-01-01 54.8927