Year	Percent
1960-01-01	5.5968599999999995
1961-01-01	6.1816600000000000
1962-01-01	7.4819100000000010
1963-01-01	8.3869400000000000
1964-01-01	9.7636100000000000
1965-01-01	9.8388300000000000
1966-01-01	9.1208200000000000
1967-01-01	9.3302700000000000
1968-01-01	9.9841699999999990
1969-01-01	11.0443000000000000
1970-01-01	11.7898000000000000
1971-01-01	12.4339000000000000
1972-01-01	16.4861000000000000
1973-01-01	16.3329000000000000
1974-01-01	14.1098000000000000
1975-01-01	14.8064000000000000
1976-01-01	15.7978000000000000
1977-01-01	14.6025000000000000
1978-01-01	14.8602000000000000
1979-01-01	16.8401000000000000
1980-01-01	16.0774000000000000
1981-01-01	15.2600000000000000
1982-01-01	15.2600000000000000
1983-01-01	15.2600000000000000
1984-01-01	15.2600000000000000
1985-01-01	15.2600000000000000
1986-01-01	15.2600000000000000
1987-01-01	15.2600000000000000
1988-01-01	15.2600000000000000
1989-01-01	15.2600000000000000
1990-01-01	15.2600000000000000
1991-01-01	15.2600000000000000
1992-01-01	15.2600000000000000
1993-01-01	15.2600000000000000
1994-01-01	15.2600000000000000
1995-01-01	15.2600000000000000
1996-01-01	15.2600000000000000
1997-01-01	15.2600000000000000
1998-01-01	15.2600000000000000
1999-01-01	15.2600000000000000
2000-01-01	15.2600000000000000
2001-01-01	15.2600000000000000
2002-01-01	15.2600000000000000
2003-01-01	15.2600000000000000
2004-01-01	15.2600000000000000
2005-01-01	15.2600000000000000
2006-01-01	15.2600000000000000
2007-01-01	15.2600000000000000
2008-01-01	15.2600000000000000
2009-01-01	1.1489500000000000
2010-01-01	1.8650700000000000
2011-01-01	1.5009200000000000
2012-01-01	2.1354300000000000
2013-01-01	2.8956700000000000
2014-01-01	2.6009000000000000
2015-01-01	2.4204000000000000
2016-01-01	2.0724299999999998