Year Percent 1990-01-01 27.5369 1991-01-01 29.3599 1992-01-01 31.7781 1993-01-01 34.6539 1994-01-01 35.6634 1995-01-01 31.5881 1996-01-01 31.6411 1997-01-01 25.1119 1998-01-01 29.1965 1999-01-01 27.9792 2000-01-01 26.2775 2001-01-01 25.8039 2002-01-01 29.3953 2003-01-01 28.7826 2004-01-01 24.2800 2005-01-01 20.4470 2006-01-01 18.4825 2007-01-01 17.2541 2008-01-01 13.6015 2009-01-01 25.3641 2010-01-01 29.1565 2011-01-01 30.2340 2012-01-01 36.1398 2013-01-01 33.4426 2014-01-01 31.5737 2015-01-01 31.2753 2016-01-01 30.7231