Year	Percent
1964-01-01	0.0970140000000000
1965-01-01	0.5240199999999999
1966-01-01	0.6385529999999999
1967-01-01	0.2504380000000000
1968-01-01	0.0166920000000000
1969-01-01	0.3988310000000000
1970-01-01	1.9619600000000000
1971-01-01	3.9541800000000005
1972-01-01	4.3156600000000000
1973-01-01	4.3377000000000000
1974-01-01	4.4150400000000000
1975-01-01	6.4608900000000000
1976-01-01	7.1573800000000000
1977-01-01	6.5168400000000000
1978-01-01	6.4822000000000000
1979-01-01	6.4893700000000000
1980-01-01	6.6106300000000005
1981-01-01	7.7332600000000005
1982-01-01	10.5794000000000000
1983-01-01	15.6977000000000000
1984-01-01	20.9967000000000000
1985-01-01	25.0657000000000000
1986-01-01	26.7132000000000000
1987-01-01	20.6145000000000000
1988-01-01	24.9550000000000000
1989-01-01	20.4333000000000000
1990-01-01	22.0335000000000000
1991-01-01	20.8209999999999980
1992-01-01	22.4787000000000000
1993-01-01	13.6602000000000000
1994-01-01	9.2180800000000000
1995-01-01	4.8792200000000000
1996-01-01	4.0677100000000000
1997-01-01	3.4730500000000000
1998-01-01	3.1395299999999997
1999-01-01	3.5271300000000000
2000-01-01	5.1600000000000000
2001-01-01	6.6134300000000000
2002-01-01	6.4850699999999994
2003-01-01	6.4289200000000000
2004-01-01	6.0472100000000000
2005-01-01	4.9732199999999995
2006-01-01	3.8697699999999995
2007-01-01	3.8684700000000000
2008-01-01	4.3931600000000000
2009-01-01	5.0552000000000000
2010-01-01	5.0503300000000010
2011-01-01	6.4395700000000000
2012-01-01	8.7809000000000000
2013-01-01	8.8689200000000000
2014-01-01	8.6128700000000000
2015-01-01	8.1215100000000000