Year	Percent
1999-01-01	43.375
2000-01-01	42.850
2001-01-01	43.075
2002-01-01	42.725
2003-01-01	43.500
2004-01-01	42.475
2005-01-01	42.500
2006-01-01	43.250
2007-01-01	44.200
2008-01-01	45.450
2009-01-01	43.850
2010-01-01	43.375
2011-01-01	43.325
2012-01-01	43.300
2013-01-01	43.625
2014-01-01	44.100
2015-01-01	45.250
2016-01-01	46.900
2017-01-01	48.250