Year Percent 1995-01-01 57.1841 1996-01-01 41.3908 1997-01-01 28.6612 1998-01-01 27.9769 1999-01-01 29.2373 2000-01-01 32.0650 2001-01-01 36.5510 2002-01-01 41.7558 2003-01-01 45.9662 2004-01-01 49.8918 2005-01-01 59.8205 2006-01-01 71.3818 2007-01-01 81.0864 2008-01-01 87.1646 2009-01-01 88.8303 2010-01-01 89.6769 2011-01-01 91.7484 2012-01-01 93.7151 2013-01-01 95.2447 2014-01-01 96.1495 2015-01-01 96.8988 2016-01-01 97.4635