Year	Percent
1999-01-01	23.625
2000-01-01	20.175
2001-01-01	17.825
2002-01-01	18.275
2003-01-01	21.200
2004-01-01	22.400
2005-01-01	22.075
2006-01-01	22.350
2007-01-01	20.900
2008-01-01	18.500
2009-01-01	22.450
2010-01-01	22.300
2011-01-01	18.700
2012-01-01	18.750
2013-01-01	22.425
2014-01-01	22.425
2015-01-01	19.975
2016-01-01	18.125
2017-01-01	18.175