Year	Percent
1964-01-01	3.5355600000000000
1965-01-01	3.1323200000000000
1966-01-01	2.6851100000000000
1967-01-01	2.3739300000000000
1968-01-01	2.7359299999999998
1969-01-01	4.6687400000000010
1970-01-01	6.5204100000000000
1971-01-01	7.7699800000000000
1972-01-01	8.1419199999999990
1973-01-01	7.3398200000000000
1974-01-01	5.5512100000000000
1975-01-01	4.0373000000000000
1976-01-01	4.3095600000000000
1977-01-01	5.2688500000000000
1978-01-01	5.9713500000000000
1979-01-01	6.4995300000000000
1980-01-01	7.5234399999999990
1981-01-01	8.2308800000000000
1982-01-01	8.8839700000000000
1983-01-01	9.6992300000000000
1984-01-01	9.3696200000000000
1985-01-01	9.1195200000000000
1986-01-01	8.6106699999999990
1987-01-01	6.9313300000000000
1988-01-01	4.1333900000000000
1989-01-01	1.9535900000000002
1990-01-01	1.8006099999999998
1991-01-01	1.9047000000000000
1992-01-01	1.6909900000000002
1993-01-01	1.4168100000000001
1994-01-01	0.8293060000000000
1995-01-01	0.5212250000000000
1996-01-01	0.6350800000000000
1997-01-01	1.2655700000000000
1998-01-01	3.3677200000000000
1999-01-01	4.2945000000000000
2000-01-01	3.1788400000000000
2001-01-01	2.7735200000000000
2002-01-01	2.5094700000000000
2003-01-01	2.0893500000000000
2004-01-01	1.8228500000000000
2005-01-01	1.5431700000000002
2006-01-01	1.5334000000000000
2007-01-01	1.9897200000000002
2008-01-01	2.6037800000000000
2009-01-01	2.9642700000000000
2010-01-01	2.8084700000000002
2011-01-01	2.6157900000000000
2012-01-01	2.2749800000000000
2013-01-01	2.0284700000000000
2014-01-01	1.8031599999999999
2015-01-01	1.7757700000000000
2016-01-01	1.9605000000000000