Year	Percent
1998-01-01	30.725
1999-01-01	30.275
2000-01-01	30.750
2001-01-01	30.450
2002-01-01	30.325
2003-01-01	29.700
2004-01-01	32.250
2005-01-01	30.425
2006-01-01	30.350
2007-01-01	29.375
2008-01-01	29.025
2009-01-01	25.925
2010-01-01	24.000
2011-01-01	22.775
2012-01-01	21.800
2013-01-01	18.700
2014-01-01	18.200
2015-01-01	18.625
2016-01-01	19.200
2017-01-01	20.100