Year	Percent
1978-12-31	12.285
1979-12-31	15.22
1980-12-31	14.095
1981-12-31	15.405
1982-12-31	10.44
1983-12-31	10
1984-12-31	10.44
1985-12-31	11.69
1986-12-31	11.125
1987-12-31	9.315
1988-12-31	12.875
1989-12-31	14.66
1990-12-31	12.845
1991-12-31	10.91
1992-12-31	6.78
1993-12-31	5.13
1994-12-31	7.91
1995-12-31	6.295
1996-12-31	6.94
1997-12-31	7.61
1998-12-31	5.515
1999-12-31	6.625
2000-12-31	5.7188
2001-12-31	4.4063
2002-12-31	3.925
2003-12-31	4.375
2004-12-31	4.87
2005-12-31	4.5
2006-12-31	5.54
2007-12-31	5.66
2008-12-31	3.1
2009-12-31	1.375
2010-12-31	1.5
2011-12-31	1.885
2012-12-31	1.01
2013-12-31	0.825
2014-12-31	1.035
2015-12-31	1.06
2016-12-31	0.78