Year	Percent
1998-01-01	39.300
1999-01-01	41.450
2000-01-01	41.875
2001-01-01	41.575
2002-01-01	43.850
2003-01-01	44.075
2004-01-01	44.700
2005-01-01	46.000
2006-01-01	45.150
2007-01-01	47.000
2008-01-01	46.675
2009-01-01	45.975
2010-01-01	47.425
2011-01-01	46.450
2012-01-01	46.950
2013-01-01	46.850
2014-01-01	47.475
2015-01-01	49.925
2016-01-01	50.950
2017-01-01	54.625