Year Percent 2001-01-01 58.8547 2002-01-01 53.1237 2003-01-01 61.5329 2004-01-01 62.9805 2005-01-01 64.7473 2006-01-01 66.8330 2007-01-01 76.8187 2008-01-01 74.4491 2009-01-01 69.5703 2010-01-01 72.3740 2011-01-01 68.9037 2012-01-01 72.0765 2013-01-01 69.0339 2014-01-01 72.3151 2015-01-01 73.5785 2016-01-01 74.5417