Year	Percent
1999-01-01	38.400
2000-01-01	38.675
2001-01-01	39.650
2002-01-01	38.875
2003-01-01	38.450
2004-01-01	37.625
2005-01-01	37.650
2006-01-01	37.400
2007-01-01	36.100
2008-01-01	35.975
2009-01-01	34.875
2010-01-01	35.200
2011-01-01	34.125
2012-01-01	34.950
2013-01-01	33.650
2014-01-01	32.275
2015-01-01	32.800
2016-01-01	30.700
2017-01-01	30.650