Year Percent 2000-01-01 55.275 2001-01-01 56.275 2002-01-01 58.525 2003-01-01 54.825 2004-01-01 54.800 2005-01-01 58.850 2006-01-01 59.150 2007-01-01 56.475 2008-01-01 55.500 2009-01-01 56.200 2010-01-01 58.850 2011-01-01 56.575 2012-01-01 55.725 2013-01-01 58.625 2014-01-01 58.625 2015-01-01 54.325 2016-01-01 53.900 2017-01-01 50.300