Year	Percent
1987-12-31	7.89
1988-12-31	8.03
1989-12-31	9.15
1990-12-31	8.21
1991-12-31	5.98
1992-12-31	3.83
1993-12-31	3.33
1994-12-31	4.99
1995-12-31	6
1996-12-31	5.49
1997-12-31	5.74
1998-12-31	5.43
1999-12-31	5.44
2000-12-31	6.6
2001-12-31	3.67
2002-12-31	1.82
2003-12-31	1.17
2004-12-31	1.75
2005-12-31	3.73
2006-12-31	5.24
2007-12-31	5.24
2008-12-31	3.12
2009-12-31	1.13
2010-12-31	0.5358
2011-12-31	0.5075
2012-12-31	0.6809