Year Percent 2002-01-01 62.2854 2003-01-01 57.6211 2004-01-01 52.8512 2005-01-01 50.8004 2006-01-01 54.0844 2007-01-01 51.7788 2008-01-01 51.8344 2009-01-01 58.3699 2010-01-01 58.2419 2011-01-01 56.9667 2012-01-01 56.9527 2013-01-01 59.1577 2014-01-01 60.9091 2015-01-01 63.4034 2016-01-01 66.2674