Year	Percent
1999-01-01	67.275
2000-01-01	67.175
2001-01-01	67.650
2002-01-01	67.475
2003-01-01	67.150
2004-01-01	68.025
2005-01-01	67.725
2006-01-01	68.350
2007-01-01	67.825
2008-01-01	68.050
2009-01-01	67.650
2010-01-01	66.700
2011-01-01	66.500
2012-01-01	65.925
2013-01-01	65.350
2014-01-01	64.850
2015-01-01	64.675
2016-01-01	66.575
2017-01-01	65.375