Year Percent 1998-01-01 55.0618 1999-01-01 41.3350 2000-01-01 39.1000 2001-01-01 43.6000 2002-01-01 44.0409 2003-01-01 47.3050 2004-01-01 50.4255 2005-01-01 61.6234 2006-01-01 61.6847 2007-01-01 68.4938 2008-01-01 66.8190 2009-01-01 66.3471 2010-01-01 67.9939 2011-01-01 64.8338 2012-01-01 62.3231 2013-01-01 62.3231 2014-01-01 67.3622 2015-01-01 71.1702 2016-01-01 67.1569