Year	Percent
1999-01-01	60.650
2000-01-01	63.550
2001-01-01	66.325
2002-01-01	67.500
2003-01-01	69.700
2004-01-01	64.650
2005-01-01	63.725
2006-01-01	63.575
2007-01-01	64.575
2008-01-01	62.600
2009-01-01	64.250
2010-01-01	65.175
2011-01-01	67.700
2012-01-01	69.975
2013-01-01	69.825
2014-01-01	69.575
2015-01-01	68.325
2016-01-01	69.450
2017-01-01	65.075