Year	Percent
1999-01-01	75.425
2000-01-01	76.525
2001-01-01	77.150
2002-01-01	79.050
2003-01-01	79.950
2004-01-01	78.850
2005-01-01	79.400
2006-01-01	80.075
2007-01-01	80.500
2008-01-01	80.925
2009-01-01	82.050
2010-01-01	82.350
2011-01-01	83.225
2012-01-01	84.000
2013-01-01	84.525
2014-01-01	84.550
2015-01-01	84.375
2016-01-01	84.900
2017-01-01	85.050