Year	Percent
1999-01-01	55.025
2000-01-01	56.850
2001-01-01	60.775
2002-01-01	64.025
2003-01-01	65.450
2004-01-01	68.575
2005-01-01	69.675
2006-01-01	69.775
2007-01-01	70.450
2008-01-01	71.300
2009-01-01	72.250
2010-01-01	72.450
2011-01-01	72.975
2012-01-01	72.100
2013-01-01	69.025
2014-01-01	66.975
2015-01-01	65.600
2016-01-01	63.850
2017-01-01	63.525