Year Percent 1989-01-01 26.8271 1990-01-01 21.6998 1991-01-01 29.6614 1992-01-01 34.8264 1993-01-01 41.7415 1994-01-01 39.0349 1995-01-01 33.8354 1996-01-01 32.6506 1997-01-01 19.6294 1998-01-01 26.6479 1999-01-01 27.0732 2000-01-01 24.7253 2001-01-01 30.6287 2002-01-01 33.2249 2003-01-01 35.7711 2004-01-01 37.1000 2005-01-01 38.0217 2006-01-01 35.0462 2007-01-01 34.5443 2008-01-01 28.5277 2009-01-01 31.0911 2010-01-01 30.5885 2011-01-01 28.7986 2012-01-01 33.5011 2013-01-01 30.2816 2014-01-01 29.8256 2015-01-01 28.1911 2016-01-01 25.6522