Year	Percent
1999-01-01	66.200
2000-01-01	68.425
2001-01-01	69.475
2002-01-01	70.500
2003-01-01	71.725
2004-01-01	72.950
2005-01-01	74.750
2006-01-01	76.100
2007-01-01	77.100
2008-01-01	75.550
2009-01-01	70.950
2010-01-01	69.975
2011-01-01	69.050
2012-01-01	66.700
2013-01-01	65.825
2014-01-01	67.400
2015-01-01	69.425
2016-01-01	71.500
2017-01-01	73.175