Year	Percent
1999-01-01	59.425
2000-01-01	57.575
2001-01-01	57.425
2002-01-01	57.800
2003-01-01	58.700
2004-01-01	58.775
2005-01-01	60.225
2006-01-01	62.375
2007-01-01	63.650
2008-01-01	65.275
2009-01-01	63.000
2010-01-01	60.700
2011-01-01	61.425
2012-01-01	61.800
2013-01-01	61.275
2014-01-01	62.200
2015-01-01	63.725
2016-01-01	65.100
2017-01-01	65.475