Year	Percent
2001-01-01	66.725
2002-01-01	66.325
2003-01-01	66.200
2004-01-01	65.975
2005-01-01	67.100
2006-01-01	67.600
2007-01-01	67.800
2008-01-01	68.175
2009-01-01	67.300
2010-01-01	67.675
2011-01-01	67.775
2012-01-01	67.825
2013-01-01	68.150
2014-01-01	68.650
2015-01-01	68.375
2016-01-01	68.475
2017-01-01	69.175