Year	Percent
1998-01-01	39.550
1999-01-01	40.300
2000-01-01	40.300
2001-01-01	39.475
2002-01-01	40.125
2003-01-01	40.800
2004-01-01	42.025
2005-01-01	42.150
2006-01-01	42.425
2007-01-01	42.350
2008-01-01	42.425
2009-01-01	43.500
2010-01-01	44.075
2011-01-01	43.775
2012-01-01	43.975
2013-01-01	43.750
2014-01-01	44.075
2015-01-01	44.750
2016-01-01	45.000
2017-01-01	44.750