Year	Percent
1998-01-01	67.325
1999-01-01	65.625
2000-01-01	64.975
2001-01-01	65.025
2002-01-01	65.425
2003-01-01	64.725
2004-01-01	64.175
2005-01-01	64.800
2006-01-01	65.275
2007-01-01	66.075
2008-01-01	66.550
2009-01-01	65.375
2010-01-01	64.975
2011-01-01	65.725
2012-01-01	66.550
2013-01-01	67.725
2014-01-01	68.975
2015-01-01	70.225
2016-01-01	71.950
2017-01-01	73.625