Year	Percent
1983-01-01	18.975
1984-01-01	18.975
1985-01-01	16.075
1986-01-01	14.375
1987-01-01	13.350
1988-01-01	12.625
1989-01-01	11.250
1990-01-01	10.450
1991-01-01	11.225
1992-01-01	13.450
1993-01-01	19.500
1994-01-01	21.550
1995-01-01	20.525
1996-01-01	18.550
1997-01-01	18.475
1998-01-01	20.175
1999-01-01	18.300
2000-01-01	14.425
2001-01-01	15.975
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