Year	Percent
1987-12-31	7.4
1988-12-31	9.33
1989-12-31	8.2
1990-12-31	7.46
1991-12-31	4.13
1992-12-31	3.54
1993-12-31	3.41
1994-12-31	6.91
1995-12-31	5.44
1996-12-31	5.5
1997-12-31	5.74
1998-12-31	4.98
1999-12-31	6.05
2000-12-31	6.14
2001-12-31	1.92
2002-12-31	1.32
2003-12-31	1.17
2004-12-31	2.73
2005-12-31	4.66
2006-12-31	5.32
2007-12-31	4.66
2008-12-31	1.78
2009-12-31	0.43
2010-12-31	0.56
2011-12-31	0.81
2012-12-31	0.51