Year	Percent
1999-01-01	38.850
2000-01-01	38.325
2001-01-01	39.075
2002-01-01	39.150
2003-01-01	38.625
2004-01-01	38.775
2005-01-01	38.250
2006-01-01	37.475
2007-01-01	37.750
2008-01-01	38.375
2009-01-01	38.600
2010-01-01	38.650
2011-01-01	38.100
2012-01-01	37.125
2013-01-01	36.125
2014-01-01	34.250
2015-01-01	32.850
2016-01-01	31.450
2017-01-01	30.425