Year	Percent
1999-01-01	65.875
2000-01-01	67.200
2001-01-01	66.525
2002-01-01	66.800
2003-01-01	67.850
2004-01-01	68.500
2005-01-01	70.350
2006-01-01	70.700
2007-01-01	72.300
2008-01-01	73.775
2009-01-01	73.775
2010-01-01	74.400
2011-01-01	73.750
2012-01-01	73.925
2013-01-01	74.000
2014-01-01	74.975
2015-01-01	74.475
2016-01-01	74.350
2017-01-01	74.625