Year	Percent
1999-01-01	52.775
2000-01-01	51.975
2001-01-01	51.775
2002-01-01	50.825
2003-01-01	50.075
2004-01-01	49.600
2005-01-01	47.450
2006-01-01	47.800
2007-01-01	47.850
2008-01-01	48.525
2009-01-01	51.800
2010-01-01	55.025
2011-01-01	57.450
2012-01-01	59.650
2013-01-01	60.425
2014-01-01	62.675
2015-01-01	63.825
2016-01-01	65.250
2017-01-01	64.900