Year	Percent
1999-01-01	60.675
2000-01-01	62.850
2001-01-01	61.275
2002-01-01	64.800
2003-01-01	67.200
2004-01-01	69.075
2005-01-01	69.800
2006-01-01	71.750
2007-01-01	73.300
2008-01-01	75.250
2009-01-01	77.175
2010-01-01	78.750
2011-01-01	79.725
2012-01-01	81.075
2013-01-01	81.800
2014-01-01	82.000
2015-01-01	82.025
2016-01-01	82.325
2017-01-01	82.000