Year	Percent
1999-01-01	61.000
2000-01-01	60.300
2001-01-01	62.325
2002-01-01	61.000
2003-01-01	60.450
2004-01-01	60.000
2005-01-01	56.975
2006-01-01	56.025
2007-01-01	56.625
2008-01-01	56.250
2009-01-01	58.275
2010-01-01	59.750
2011-01-01	60.775
2012-01-01	62.350
2013-01-01	64.100
2014-01-01	66.000
2015-01-01	66.825
2016-01-01	68.725
2017-01-01	68.525