Year	Percent
1980-01-01	8.0000000000000000
1981-01-01	9.1000000000000000
1982-01-01	9.4000000000000000
1983-01-01	8.9000000000000000
1984-01-01	8.2500000000000000
1985-01-01	3.3500000000000000
1986-01-01	5.0000000000000000
1987-01-01	4.7300000000000000
1988-01-01	4.9500000000000000
1989-01-01	4.7600000000000000
1990-01-01	4.4700000000000000
1991-01-01	4.5900000000000000
1992-01-01	3.5800000000000000
1993-01-01	3.6600000000000000
1994-01-01	3.1700000000000000
1995-01-01	2.6500000000000000
1996-01-01	2.5300000000000000
1997-01-01	2.3700000000000000
1998-01-01	2.5600000000000000
1999-01-01	2.2300000000000000
2000-01-01	2.2000000000000000
2001-01-01	2.2600000000000000
2002-01-01	2.2500000000000000
2003-01-01	2.6100000000000000
2004-01-01	2.5600000000000000
2005-01-01	2.2100000000000000
2006-01-01	1.8700000000000000
2007-01-01	1.7881099999999999
2008-01-01	1.7808500000000000
2009-01-01	2.0000000000000000