Year	Percent
1999-01-01	39.725
2000-01-01	41.250
2001-01-01	40.000
2002-01-01	39.575
2003-01-01	40.400
2004-01-01	36.625
2005-01-01	38.525
2006-01-01	41.875
2007-01-01	45.950
2008-01-01	48.925
2009-01-01	49.075
2010-01-01	49.900
2011-01-01	48.175
2012-01-01	50.175
2013-01-01	52.800
2014-01-01	54.275
2015-01-01	54.075
2016-01-01	57.575
2017-01-01	60.125