Year	Percent
1998-01-01	38.000
1999-01-01	38.050
2000-01-01	38.050
2001-01-01	38.250
2002-01-01	38.075
2003-01-01	37.850
2004-01-01	38.400
2005-01-01	38.925
2006-01-01	39.175
2007-01-01	39.550
2008-01-01	39.600
2009-01-01	40.400
2010-01-01	40.925
2011-01-01	41.275
2012-01-01	40.750
2013-01-01	41.350
2014-01-01	41.300
2015-01-01	41.125
2016-01-01	40.750
2017-01-01	40.650