Year	Percent
1999-01-01	78.000
2000-01-01	79.300
2001-01-01	80.100
2002-01-01	80.000
2003-01-01	79.225
2004-01-01	81.200
2005-01-01	81.100
2006-01-01	81.225
2007-01-01	82.400
2008-01-01	84.775
2009-01-01	83.175
2010-01-01	82.075
2011-01-01	81.375
2012-01-01	81.050
2013-01-01	79.325
2014-01-01	79.050
2015-01-01	79.550
2016-01-01	81.200
2017-01-01	83.525