Year	Percent
1999-01-01	66.075
2000-01-01	66.850
2001-01-01	66.975
2002-01-01	66.475
2003-01-01	67.450
2004-01-01	66.950
2005-01-01	67.225
2006-01-01	67.775
2007-01-01	67.875
2008-01-01	67.950
2009-01-01	66.900
2010-01-01	67.025
2011-01-01	66.625
2012-01-01	69.050
2013-01-01	70.050
2014-01-01	73.175
2015-01-01	74.425
2016-01-01	76.200
2017-01-01	77.175