Year	Percent
1999-01-01	61.950
2000-01-01	62.000
2001-01-01	62.525
2002-01-01	63.750
2003-01-01	64.300
2004-01-01	63.500
2005-01-01	64.900
2006-01-01	65.975
2007-01-01	67.075
2008-01-01	67.825
2009-01-01	68.725
2010-01-01	68.900
2011-01-01	69.250
2012-01-01	70.025
2013-01-01	70.650
2014-01-01	70.800
2015-01-01	70.900
2016-01-01	71.675
2017-01-01	71.825