Year Percent 1996-01-01 26.6298 1997-01-01 32.8239 1998-01-01 25.5022 1999-01-01 24.8973 2000-01-01 24.8394 2001-01-01 21.7771 2002-01-01 24.2095 2003-01-01 28.8535 2004-01-01 30.7385 2005-01-01 30.4323 2006-01-01 33.4395 2007-01-01 36.0892 2008-01-01 29.9415 2009-01-01 30.2614 2010-01-01 26.5925 2011-01-01 25.7402 2012-01-01 22.5282 2013-01-01 22.7501 2014-01-01 23.7873 2015-01-01 26.4413 2016-01-01 19.6139