Year	Percent
1983-01-01	16.800
1984-01-01	12.925
1985-01-01	9.750
1986-01-01	6.600
1987-01-01	7.225
1988-01-01	8.125
1989-01-01	10.325
1990-01-01	10.875
1991-01-01	10.700
1992-01-01	11.825
1993-01-01	13.100
1994-01-01	10.250
1995-01-01	8.200
1996-01-01	8.525
1997-01-01	6.725
1998-01-01	7.050
1999-01-01	9.350
2000-01-01	6.575
2001-01-01	8.125
2002-01-01	7.350
2003-01-01	9.125
2004-01-01	8.900
2005-01-01	8.650
2006-01-01	7.875
2007-01-01	7.575
2008-01-01	7.300
2009-01-01	13.200
2010-01-01	16.000
2011-01-01	15.575
2012-01-01	14.675
2013-01-01	14.175
2014-01-01	13.650
2015-01-01	11.550
2016-01-01	13.075
2017-01-01	11.325