Year	Percent
1960-01-01	2.4426000000000000
1961-01-01	3.3220699999999996
1962-01-01	4.0650300000000000
1963-01-01	5.2384200000000000
1964-01-01	6.3599800000000000
1965-01-01	6.3802900000000005
1966-01-01	5.9312100000000000
1967-01-01	3.6811199999999995
1968-01-01	1.3155800000000000
1969-01-01	1.4724700000000002
1970-01-01	1.7168800000000000
1971-01-01	2.3914500000000000
1972-01-01	2.6633600000000000
1973-01-01	2.5487599999999997
1974-01-01	2.6869400000000003
1975-01-01	2.8356100000000000
1976-01-01	2.4916500000000000
1977-01-01	2.0014200000000000
1978-01-01	2.3995200000000000
1979-01-01	3.5235300000000005
1980-01-01	4.3818000000000000
1981-01-01	5.6386900000000000
1982-01-01	6.9710399999999995
1983-01-01	6.5142900000000000
1984-01-01	6.4600100000000000
1985-01-01	7.0708699999999990
1986-01-01	7.0330500000000000
1987-01-01	7.2656100000000010
1988-01-01	9.0948000000000000
1989-01-01	10.2382000000000000
1990-01-01	10.2149000000000000
1991-01-01	8.3221100000000000
1992-01-01	6.0838199999999990
1993-01-01	6.1641699999999995
1994-01-01	4.9951500000000000
1995-01-01	3.0959100000000000
1996-01-01	2.2894600000000000
1997-01-01	1.9534500000000000
1998-01-01	1.8305700000000000
1999-01-01	1.5857200000000000
2000-01-01	1.1668500000000000
2001-01-01	3.1836800000000000
2002-01-01	5.3076500000000000
2003-01-01	5.8680600000000000
2004-01-01	6.3636800000000004
2005-01-01	6.1883800000000000
2006-01-01	5.7009700000000000
2007-01-01	5.0971100000000000
2008-01-01	4.8507200000000000
2009-01-01	5.4322000000000000
2010-01-01	6.4275800000000000
2011-01-01	6.8081900000000000
2012-01-01	6.6997399999999990
2013-01-01	6.5623600000000010
2014-01-01	5.9553100000000000
2015-01-01	5.2902100000000000
2016-01-01	4.8345300000000000