Year	Percent
1987-12-31	7.54
1988-12-31	7.8
1989-12-31	9.17
1990-12-31	8.17
1991-12-31	5.87
1992-12-31	3.7
1993-12-31	3.16
1994-12-31	4.53
1995-12-31	5.92
1996-12-31	5.39
1997-12-31	5.59
1998-12-31	5.47
1999-12-31	5.24
2000-12-31	6.41
2001-12-31	3.76
2002-12-31	1.72
2003-12-31	1.16
2004-12-31	1.51
2005-12-31	3.44
2006-12-31	5.12
2007-12-31	5.27
2008-12-31	2.93
2009-12-31	0.56
2010-12-31	0.3169
2011-12-31	0.2821
2012-12-31	0.3346