Year	Percent
1981-12-31	13.75
1982-12-31	9.375
1983-12-31	10.0625
1984-12-31	8.75
1985-12-31	8
1986-12-31	6.375
1987-12-31	7.438
1988-12-31	9.313
1989-12-31	8.375
1990-12-31	7.5625
1991-12-31	4.25
1992-12-31	3.4375
1993-12-31	3.375
1994-12-31	6.5
1995-12-31	5.63
1996-12-31	5.56
1997-12-31	5.75
1998-12-31	5.06
1999-12-31	6.03
2000-12-31	6.41
2001-12-31	1.86
2002-12-31	1.37
2003-12-31	1.14
2004-12-31	2.58
2005-12-31	4.54
2006-12-31	5.38
2007-12-31	4.82
2008-12-31	1.66
2009-12-31	0.53
2010-12-31	0.48
2011-12-31	0.78
2012-12-31	0.48
2013-12-31	0.4
2014-12-31	0.5
2015-12-31	0.81
2016-12-31	1.01
2017-12-31	1.86
2018-12-31	2.97
2019-12-31	2.02