Year Percent 1999-01-01 32.1933 2000-01-01 38.0763 2001-01-01 39.4264 2002-01-01 52.3499 2003-01-01 54.6937 2004-01-01 59.6976 2005-01-01 58.3253 2006-01-01 62.7891 2007-01-01 68.3198 2008-01-01 63.0899 2009-01-01 70.0860 2010-01-01 68.7104 2011-01-01 65.9734 2012-01-01 74.9949 2013-01-01 67.5866 2014-01-01 62.8628 2015-01-01 60.9593 2016-01-01 54.6523