Year	Percent
1999-01-01	61.800
2000-01-01	63.500
2001-01-01	64.525
2002-01-01	64.925
2003-01-01	65.650
2004-01-01	66.225
2005-01-01	67.775
2006-01-01	68.875
2007-01-01	69.150
2008-01-01	66.725
2009-01-01	60.475
2010-01-01	58.825
2011-01-01	57.425
2012-01-01	54.550
2013-01-01	53.325
2014-01-01	54.200
2015-01-01	56.100
2016-01-01	57.675
2017-01-01	59.100