Year	Percent
1999-01-01	71.850
2000-01-01	71.900
2001-01-01	72.850
2002-01-01	72.500
2003-01-01	72.000
2004-01-01	74.450
2005-01-01	75.100
2006-01-01	74.900
2007-01-01	75.825
2008-01-01	75.775
2009-01-01	75.600
2010-01-01	75.375
2011-01-01	73.850
2012-01-01	73.700
2013-01-01	74.200
2014-01-01	74.375
2015-01-01	75.350
2016-01-01	74.525
2017-01-01	77.075