Year	Percent
1999-01-01	24.625
2000-01-01	26.650
2001-01-01	27.550
2002-01-01	28.400
2003-01-01	28.875
2004-01-01	29.475
2005-01-01	32.975
2006-01-01	34.500
2007-01-01	34.000
2008-01-01	32.600
2009-01-01	26.650
2010-01-01	24.275
2011-01-01	21.975
2012-01-01	18.275
2013-01-01	16.300
2014-01-01	15.975
2015-01-01	17.275
2016-01-01	17.250
2017-01-01	19.700