Year	Percent
1960-01-01	8.8952200000000000
1961-01-01	8.3115200000000000
1962-01-01	7.6329199999999995
1963-01-01	7.2057400000000000
1964-01-01	6.8235399999999995
1965-01-01	6.2230400000000000
1966-01-01	5.8740300000000000
1967-01-01	6.3067400000000005
1968-01-01	5.2276500000000000
1969-01-01	3.2686400000000000
1970-01-01	2.6913000000000000
1971-01-01	1.8923800000000000
1972-01-01	0.8610120000000001
1973-01-01	1.0289100000000000
1974-01-01	3.2303000000000000
1975-01-01	5.0242500000000000
1976-01-01	5.5767600000000000
1977-01-01	7.0188100000000000
1978-01-01	6.5989000000000000
1979-01-01	5.6826200000000000
1980-01-01	4.7682699999999990
1981-01-01	4.6483600000000000
1982-01-01	4.7972900000000000
1983-01-01	4.2281100000000000
1984-01-01	4.8866600000000000
1985-01-01	4.0808800000000005
1986-01-01	2.6025700000000000
1987-01-01	3.3685699999999996
1988-01-01	4.1788600000000000
1989-01-01	4.9167500000000000
1990-01-01	4.4534600000000000
1991-01-01	3.7853199999999996
1992-01-01	3.2850099999999998
1993-01-01	2.8292599999999997
1994-01-01	3.0710100000000000
1995-01-01	3.3242400000000000
1996-01-01	3.5093900000000002
1997-01-01	3.6586700000000000
1998-01-01	3.6088400000000003
1999-01-01	3.0540900000000000
2000-01-01	2.6410800000000000
2001-01-01	2.7485500000000000
2002-01-01	2.7031600000000000
2003-01-01	2.7004000000000000
2004-01-01	2.9235900000000004
2005-01-01	3.1510300000000000
2006-01-01	3.0942600000000000
2007-01-01	2.7918300000000000
2008-01-01	2.6291300000000000
2009-01-01	2.7643800000000000
2010-01-01	2.7447200000000000