Year Percent 2000-01-01 51.150 2001-01-01 51.875 2002-01-01 55.800 2003-01-01 58.225 2004-01-01 59.150 2005-01-01 59.500 2006-01-01 60.425 2007-01-01 64.025 2008-01-01 65.875 2009-01-01 67.600 2010-01-01 67.350 2011-01-01 67.550 2012-01-01 70.625 2013-01-01 74.250 2014-01-01 75.475 2015-01-01 77.650 2016-01-01 78.250 2017-01-01 78.975