Year	Percent
1964-01-01	18.8201000000000000
1965-01-01	14.0228000000000000
1966-01-01	13.3794000000000000
1967-01-01	14.5086000000000000
1968-01-01	15.2152000000000000
1969-01-01	15.5865000000000000
1970-01-01	8.6905000000000000
1971-01-01	8.2981699999999990
1972-01-01	9.2098300000000000
1973-01-01	10.6553000000000000
1974-01-01	11.6623000000000000
1975-01-01	11.5984000000000000
1976-01-01	10.6874000000000000
1977-01-01	11.1690000000000000
1978-01-01	11.8668000000000000
1979-01-01	11.7911000000000000
1980-01-01	10.2349000000000000
1981-01-01	11.1489000000000000
1982-01-01	11.7848000000000000
1983-01-01	11.0705000000000000
1984-01-01	11.5276000000000000
1985-01-01	11.4729000000000000
1986-01-01	11.5532000000000000
1987-01-01	13.1374000000000000
1988-01-01	13.0040000000000010
1989-01-01	12.0843000000000000
1990-01-01	11.8245000000000000
1991-01-01	10.2164000000000000
1992-01-01	11.7687000000000000
1993-01-01	10.3070000000000000
1994-01-01	11.9153000000000000
1995-01-01	9.1603300000000000
1996-01-01	8.4065600000000000
1997-01-01	7.8296600000000005
1998-01-01	8.0577899999999990
1999-01-01	8.4671899999999990
2000-01-01	8.5705800000000000
2001-01-01	9.5320700000000000
2002-01-01	9.5421800000000000
2003-01-01	10.1457000000000000
2004-01-01	10.7385000000000000
2005-01-01	11.5346000000000000
2006-01-01	10.7503000000000000
2007-01-01	11.8655000000000000
2008-01-01	14.8482000000000000
2009-01-01	17.7384000000000000
2010-01-01	19.2234000000000000
2011-01-01	21.5034000000000000
2012-01-01	23.0069999999999980
2013-01-01	22.1871000000000000
2014-01-01	22.2072000000000000
2015-01-01	21.3141000000000000
2016-01-01	20.8903000000000000