Year Percent 1990-01-01 44.3068 1991-01-01 39.1915 1992-01-01 37.1491 1993-01-01 38.7625 1994-01-01 39.6825 1995-01-01 36.9991 1996-01-01 32.4105 1997-01-01 33.1161 1998-01-01 36.3719 1999-01-01 29.9873 2000-01-01 30.1490 2001-01-01 30.0639 2002-01-01 31.3746 2003-01-01 32.8735 2004-01-01 32.6521 2005-01-01 29.7531 2006-01-01 30.5088 2007-01-01 31.7805 2008-01-01 31.4203 2009-01-01 35.5970 2010-01-01 29.8732 2011-01-01 31.3376 2012-01-01 30.7086 2013-01-01 32.7087