Year	Percent
1999-01-01	39.450
2000-01-01	40.850
2001-01-01	39.900
2002-01-01	42.200
2003-01-01	43.850
2004-01-01	45.200
2005-01-01	46.475
2006-01-01	47.900
2007-01-01	48.975
2008-01-01	50.375
2009-01-01	51.450
2010-01-01	52.150
2011-01-01	52.800
2012-01-01	53.450
2013-01-01	53.375
2014-01-01	53.100
2015-01-01	53.100
2016-01-01	53.050
2017-01-01	52.625