Year	Percent
1964-01-01	3.8502800000000000
1965-01-01	3.9870699999999997
1966-01-01	3.4588699999999997
1967-01-01	3.2974699999999997
1968-01-01	3.8261199999999995
1969-01-01	3.8182400000000003
1970-01-01	3.6359900000000000
1971-01-01	4.9192900000000000
1972-01-01	5.7521700000000000
1973-01-01	5.5915000000000000
1974-01-01	5.6956400000000000
1975-01-01	5.1132100000000000
1976-01-01	5.2103000000000000
1977-01-01	5.5533100000000000
1978-01-01	6.1467900000000000
1979-01-01	5.8574699999999990
1980-01-01	4.9222700000000000
1981-01-01	5.5574600000000000
1982-01-01	5.6612400000000000
1983-01-01	6.6589600000000000
1984-01-01	6.6843200000000000
1985-01-01	6.3307300000000000
1986-01-01	7.2128100000000000
1987-01-01	7.0115800000000000
1988-01-01	7.4642600000000000
1989-01-01	8.3486900000000000
1990-01-01	9.0277700000000000
1991-01-01	9.9003800000000000
1992-01-01	10.3857000000000000
1993-01-01	10.7820000000000000
1994-01-01	12.5370000000000000
1995-01-01	13.2040000000000000
1996-01-01	12.3584000000000000
1997-01-01	10.8765000000000000
1998-01-01	9.7781800000000000
1999-01-01	9.4924000000000000
2000-01-01	10.8475000000000000
2001-01-01	11.4401000000000000
2002-01-01	13.1174000000000000
2003-01-01	16.1255000000000000
2004-01-01	15.5004000000000000
2005-01-01	15.9440000000000000
2006-01-01	18.2019000000000000
2007-01-01	18.5614000000000000
2008-01-01	18.0538000000000000
2009-01-01	18.4850000000000000
2010-01-01	19.4972000000000000
2011-01-01	20.1444000000000000
2012-01-01	19.6331000000000000
2013-01-01	18.6600000000000000
2014-01-01	18.4302000000000000
2015-01-01	18.8509000000000000
2016-01-01	17.0423000000000000