Year	Percent
1999-01-01	21.025
2000-01-01	17.425
2001-01-01	16.875
2002-01-01	17.700
2003-01-01	21.725
2004-01-01	21.100
2005-01-01	21.475
2006-01-01	20.475
2007-01-01	18.875
2008-01-01	17.825
2009-01-01	21.900
2010-01-01	22.400
2011-01-01	18.675
2012-01-01	19.675
2013-01-01	23.675
2014-01-01	23.300
2015-01-01	22.100
2016-01-01	20.125
2017-01-01	19.300