Year	Percent
1999-01-01	51.150
2000-01-01	50.975
2001-01-01	48.000
2002-01-01	47.050
2003-01-01	44.075
2004-01-01	43.525
2005-01-01	43.175
2006-01-01	43.250
2007-01-01	44.875
2008-01-01	46.975
2009-01-01	46.500
2010-01-01	44.150
2011-01-01	41.975
2012-01-01	41.075
2013-01-01	40.125
2014-01-01	39.700
2015-01-01	37.400
2016-01-01	33.650
2017-01-01	32.400