Year	Percent
1999-01-01	15.800
2000-01-01	14.000
2001-01-01	10.600
2002-01-01	11.500
2003-01-01	11.525
2004-01-01	11.025
2005-01-01	9.200
2006-01-01	8.500
2007-01-01	8.300
2008-01-01	11.325
2009-01-01	17.975
2010-01-01	19.975
2011-01-01	21.525
2012-01-01	24.900
2013-01-01	26.225
2014-01-01	24.550
2015-01-01	22.175
2016-01-01	19.725
2017-01-01	17.325