Year Percent 1996-01-01 24.2421 1997-01-01 35.8538 1998-01-01 33.1651 1999-01-01 46.4650 2000-01-01 45.1867 2001-01-01 54.5479 2002-01-01 66.3993 2003-01-01 74.3984 2004-01-01 71.0592 2005-01-01 53.4719 2006-01-01 45.9761 2007-01-01 37.0496 2008-01-01 33.9711 2009-01-01 41.8481 2010-01-01 31.9694 2011-01-01 32.9809 2012-01-01 32.6848 2013-01-01 36.4154 2014-01-01 28.5548 2015-01-01 36.3753 2016-01-01 27.6477