Year	Percent
1999-01-01	18.850
2000-01-01	15.200
2001-01-01	16.175
2002-01-01	17.200
2003-01-01	22.150
2004-01-01	20.050
2005-01-01	20.975
2006-01-01	18.750
2007-01-01	17.075
2008-01-01	17.275
2009-01-01	21.425
2010-01-01	22.450
2011-01-01	18.675
2012-01-01	20.400
2013-01-01	24.725
2014-01-01	23.975
2015-01-01	23.800
2016-01-01	21.725
2017-01-01	20.200