Year	Percent
1964-01-01	2.6691200000000000
1965-01-01	2.6572900000000000
1966-01-01	2.4739500000000000
1967-01-01	2.7000599999999997
1968-01-01	3.3047000000000000
1969-01-01	3.1708300000000000
1970-01-01	3.0851800000000000
1971-01-01	4.4399600000000000
1972-01-01	5.2131200000000000
1973-01-01	4.9941200000000000
1974-01-01	6.9998700000000000
1975-01-01	6.0282100000000000
1976-01-01	4.0675200000000000
1977-01-01	4.2518900000000000
1978-01-01	5.6171200000000000
1979-01-01	7.6715100000000005
1980-01-01	7.7883600000000010
1981-01-01	10.4618000000000000
1982-01-01	11.3270000000000000
1983-01-01	10.9075000000000000
1984-01-01	8.9637300000000000
1985-01-01	6.5734800000000000
1986-01-01	7.5984300000000005
1987-01-01	8.9775300000000000
1988-01-01	10.2679999999999990
1989-01-01	11.3292000000000000
1990-01-01	12.4299000000000000
1991-01-01	13.9016000000000000
1992-01-01	14.7977000000000000
1993-01-01	14.8014000000000000
1994-01-01	16.5962000000000000
1995-01-01	18.4932000000000000
1996-01-01	17.9308000000000000
1997-01-01	15.5500000000000000
1998-01-01	15.7203000000000000
1999-01-01	15.2750000000000000
2000-01-01	17.2088000000000000
2001-01-01	18.7983000000000000
2002-01-01	20.3483000000000000
2003-01-01	21.7816000000000000
2004-01-01	18.3526000000000000
2005-01-01	16.3753000000000000
2006-01-01	16.0882000000000000
2007-01-01	15.8268000000000000
2008-01-01	14.3245000000000000
2009-01-01	14.4726000000000000
2010-01-01	16.9840000000000000
2011-01-01	20.4411000000000000
2012-01-01	21.5161000000000000
2013-01-01	19.5599000000000000
2014-01-01	18.6009000000000000
2015-01-01	18.6413000000000000
2016-01-01	16.9107000000000000