Year	Percent
1999-01-01	70.025
2000-01-01	70.425
2001-01-01	70.150
2002-01-01	69.850
2003-01-01	71.025
2004-01-01	70.950
2005-01-01	72.100
2006-01-01	73.150
2007-01-01	73.225
2008-01-01	73.350
2009-01-01	73.575
2010-01-01	74.525
2011-01-01	74.350
2012-01-01	76.475
2013-01-01	77.100
2014-01-01	78.825
2015-01-01	79.600
2016-01-01	79.825
2017-01-01	80.400