Year	Percent
1999-01-01	37.675
2000-01-01	36.825
2001-01-01	36.325
2002-01-01	36.825
2003-01-01	36.525
2004-01-01	37.050
2005-01-01	38.500
2006-01-01	39.075
2007-01-01	39.250
2008-01-01	38.650
2009-01-01	39.400
2010-01-01	38.700
2011-01-01	39.150
2012-01-01	38.325
2013-01-01	37.550
2014-01-01	37.125
2015-01-01	35.725
2016-01-01	34.625
2017-01-01	34.125