Year Percent 1996-01-01 32.7519 1997-01-01 34.1772 1998-01-01 34.0577 1999-01-01 36.1922 2000-01-01 32.8698 2001-01-01 31.7943 2002-01-01 28.9748 2003-01-01 32.0240 2004-01-01 43.8429 2005-01-01 36.2966 2006-01-01 33.8213 2007-01-01 37.5650 2008-01-01 41.0022 2009-01-01 23.3788 2010-01-01 30.1074 2011-01-01 29.5853 2012-01-01 22.8031 2013-01-01 37.2340 2014-01-01 36.1069