Year	Percent
1966-01-01	2.8895600000000000
1967-01-01	3.0612200000000000
1968-01-01	2.9399500000000000
1969-01-01	2.6650300000000000
1970-01-01	2.5301000000000000
1971-01-01	4.1625100000000000
1972-01-01	5.2974200000000000
1973-01-01	6.2309800000000010
1974-01-01	7.0790500000000000
1975-01-01	6.9026000000000000
1976-01-01	8.0396399999999990
1977-01-01	5.5798900000000000
1978-01-01	5.5717500000000000
1979-01-01	4.8880400000000000
1980-01-01	5.8303100000000000
1981-01-01	6.4535599999999995
1982-01-01	6.2303900000000000
1983-01-01	15.8051000000000000
1984-01-01	18.1889000000000000
1985-01-01	18.5410000000000000
1986-01-01	13.1105000000000000
1987-01-01	13.1105000000000000
1988-01-01	13.1105000000000000
1989-01-01	13.1105000000000000
1990-01-01	13.1105000000000000
1991-01-01	13.1105000000000000
1992-01-01	25.1875000000000000
1993-01-01	19.9672000000000000
1994-01-01	19.2874000000000000
1995-01-01	19.3144000000000000
1996-01-01	19.4841000000000000
1997-01-01	18.6963000000000000
1998-01-01	18.5087000000000000
1999-01-01	19.6287000000000000
2000-01-01	18.7896000000000000
2001-01-01	15.0724000000000000
2002-01-01	12.0376000000000000
2003-01-01	11.7551000000000000
2004-01-01	10.3758000000000000
2005-01-01	9.8563200000000000
2006-01-01	8.2741500000000000
2007-01-01	8.2149900000000000
2008-01-01	8.4714100000000000
2009-01-01	7.6267600000000010
2010-01-01	8.0762000000000000
2011-01-01	9.7850800000000000
2012-01-01	10.8535000000000000
2013-01-01	11.8333000000000000
2014-01-01	7.6940700000000000
2015-01-01	2.9227400000000000
2016-01-01	2.7488599999999996