Year	Percent
1998-01-01	66.250
1999-01-01	67.025
2000-01-01	67.950
2001-01-01	69.150
2002-01-01	70.075
2003-01-01	70.750
2004-01-01	72.325
2005-01-01	72.300
2006-01-01	73.250
2007-01-01	73.400
2008-01-01	73.450
2009-01-01	71.850
2010-01-01	71.075
2011-01-01	71.125
2012-01-01	70.375
2013-01-01	68.525
2014-01-01	67.850
2015-01-01	68.200
2016-01-01	68.850
2017-01-01	69.425