Year Percent 1995-01-01 25.3445769732035 1996-01-01 25.4364408166704 1997-01-01 25.1333350978068 1998-01-01 24.7779910211189 1999-01-01 24.2002433267777 2000-01-01 23.8505169737859 2001-01-01 23.6673614938760 2002-01-01 22.6074625963666 2003-01-01 21.8414060303035 2004-01-01 21.8700431256358 2005-01-01 22.2714380631736 2006-01-01 22.2897066148695 2007-01-01 21.7364863085594 2008-01-01 21.6147423841648 2009-01-01 22.0451472048972 2010-01-01 22.1935767460334 2011-01-01 22.2472102688996 2012-01-01 22.2076705448431 2013-01-01 21.9679803952220 2014-01-01 22.2397320964322 2015-01-01 22.0336981942306 2016-01-01 21.8899376742237 2017-01-01 21.5433201862775