Year	Percent
1999-01-01	50.050
2000-01-01	52.000
2001-01-01	50.850
2002-01-01	53.800
2003-01-01	55.775
2004-01-01	57.375
2005-01-01	58.875
2006-01-01	60.675
2007-01-01	61.900
2008-01-01	63.575
2009-01-01	65.100
2010-01-01	66.225
2011-01-01	67.325
2012-01-01	68.375
2013-01-01	68.750
2014-01-01	68.800
2015-01-01	69.050
2016-01-01	69.200
2017-01-01	68.825