Year	Percent
1964-01-01	2.1031000000000000
1965-01-01	2.6570400000000003
1966-01-01	3.3394900000000000
1967-01-01	3.6410900000000000
1968-01-01	3.8060199999999997
1969-01-01	3.7631099999999997
1970-01-01	3.9794400000000003
1971-01-01	3.6771599999999998
1972-01-01	4.6870500000000000
1973-01-01	5.5435900000000000
1974-01-01	5.0670400000000000
1975-01-01	3.4039699999999997
1976-01-01	2.7251900000000000
1977-01-01	2.2895300000000000
1978-01-01	1.8390700000000000
1979-01-01	1.6674200000000001
1980-01-01	1.4453900000000000
1981-01-01	1.3617600000000000
1982-01-01	1.6466300000000000
1983-01-01	2.2306700000000000
1984-01-01	2.4425000000000000
1985-01-01	2.1340500000000000
1986-01-01	2.2623500000000000
1987-01-01	3.2384800000000000
1988-01-01	3.6884699999999997
1989-01-01	3.9511500000000000
1990-01-01	6.5884000000000000
1991-01-01	8.7534200000000000
1992-01-01	9.4155199999999990
1993-01-01	11.8819000000000000
1994-01-01	11.8819000000000000
1995-01-01	10.2322000000000000
1996-01-01	8.4231500000000000
1997-01-01	6.9895500000000000
1998-01-01	7.2098900000000000
1999-01-01	7.8889800000000000
2000-01-01	7.0879699999999990
2001-01-01	6.0704900000000000
2002-01-01	5.6459400000000000
2003-01-01	4.6178500000000000
2004-01-01	3.8919200000000000
2005-01-01	3.2188400000000000
2006-01-01	2.6722300000000000
2007-01-01	2.2318900000000000
2008-01-01	1.7750400000000002
2009-01-01	1.6438099999999998
2010-01-01	1.7428700000000001
2011-01-01	1.4366600000000000
2012-01-01	1.0932899999999999
2013-01-01	0.9937600000000001
2014-01-01	0.9303350000000000
2015-01-01	0.9030720000000000
2016-01-01	0.7878550000000000