Year Percent 1996-01-01 36.8126 1997-01-01 32.9761 1998-01-01 32.4505 1999-01-01 33.6774 2000-01-01 30.4300 2001-01-01 35.7903 2002-01-01 37.9725 2003-01-01 35.2068 2004-01-01 38.9263 2005-01-01 36.3061 2006-01-01 40.7274 2007-01-01 38.8673 2008-01-01 27.3640 2009-01-01 32.7286 2010-01-01 29.1944 2011-01-01 32.0628 2012-01-01 42.8358 2013-01-01 57.3022 2014-01-01 37.9722