Year	Percent
1999-01-01	63.575
2000-01-01	63.525
2001-01-01	63.750
2002-01-01	64.300
2003-01-01	64.850
2004-01-01	63.250
2005-01-01	63.975
2006-01-01	64.575
2007-01-01	65.525
2008-01-01	65.800
2009-01-01	66.075
2010-01-01	66.050
2011-01-01	66.200
2012-01-01	66.450
2013-01-01	66.650
2014-01-01	66.525
2015-01-01	66.900
2016-01-01	67.650
2017-01-01	67.925