Year	Percent
1999-01-01	58.100
2000-01-01	56.775
2001-01-01	56.825
2002-01-01	56.800
2003-01-01	57.725
2004-01-01	56.975
2005-01-01	57.700
2006-01-01	59.425
2007-01-01	60.700
2008-01-01	62.250
2009-01-01	60.175
2010-01-01	58.775
2011-01-01	59.325
2012-01-01	59.725
2013-01-01	59.850
2014-01-01	60.975
2015-01-01	62.725
2016-01-01	64.850
2017-01-01	66.175