Year	Percent
1999-01-01	64.300
2000-01-01	62.225
2001-01-01	62.025
2002-01-01	62.375
2003-01-01	63.325
2004-01-01	63.175
2005-01-01	64.600
2006-01-01	66.975
2007-01-01	68.400
2008-01-01	69.950
2009-01-01	67.550
2010-01-01	65.175
2011-01-01	66.100
2012-01-01	66.675
2013-01-01	66.375
2014-01-01	67.650
2015-01-01	69.425
2016-01-01	71.375
2017-01-01	71.975