Year	Percent
1966-01-01	0.8122910000000000
1967-01-01	0.9002370000000001
1968-01-01	0.9130070000000000
1969-01-01	0.7902220000000000
1970-01-01	1.0690300000000000
1971-01-01	1.3144300000000000
1972-01-01	1.4540000000000000
1973-01-01	1.6648400000000000
1974-01-01	2.7179500000000000
1975-01-01	2.7600800000000000
1976-01-01	2.9113599999999997
1977-01-01	4.9772800000000000
1978-01-01	5.1084200000000000
1979-01-01	4.4056000000000000
1980-01-01	4.3249800000000000
1981-01-01	4.7905600000000000
1982-01-01	5.0808599999999995
1983-01-01	4.2717500000000000
1984-01-01	3.6716900000000003
1985-01-01	3.3901800000000004
1986-01-01	3.0329500000000000
1987-01-01	2.5500300000000000
1988-01-01	2.4752600000000000
1989-01-01	3.1568400000000003
1990-01-01	4.4344900000000000
1991-01-01	5.7358100000000000
1992-01-01	6.4514300000000000
1993-01-01	5.5870700000000000
1994-01-01	5.0987100000000000
1995-01-01	3.6097400000000000
1996-01-01	1.8893200000000000
1997-01-01	1.3913700000000000
1998-01-01	0.9920150000000000
1999-01-01	1.0906700000000000
2000-01-01	0.7906260000000000
2001-01-01	0.5406310000000001
2002-01-01	0.7906090000000000
2003-01-01	0.6885870000000000
2004-01-01	0.8593629999999999
2005-01-01	1.9277500000000000
2006-01-01	2.2336800000000000
2007-01-01	1.6266200000000002
2008-01-01	2.6072300000000000
2009-01-01	3.9695300000000002
2010-01-01	4.2014500000000000
2011-01-01	5.0205100000000000