Year	Percent
1964-01-01	0.3573520000000000
1965-01-01	0.3997750000000000
1966-01-01	0.7347560000000001
1967-01-01	0.9557240000000000
1968-01-01	0.8578899999999999
1969-01-01	0.8334410000000000
1970-01-01	1.4612300000000000
1971-01-01	2.0019299999999998
1972-01-01	1.8428799999999999
1973-01-01	1.8934799999999998
1974-01-01	2.7997799999999997
1975-01-01	2.9132300000000000
1976-01-01	2.6367200000000000
1977-01-01	3.4672000000000000
1978-01-01	4.6646900000000000
1979-01-01	4.1278400000000000
1980-01-01	3.9943199999999996
1981-01-01	4.7314200000000000
1982-01-01	5.2562500000000000
1983-01-01	5.1109400000000000
1984-01-01	5.2895199999999996
1985-01-01	6.2118300000000000
1986-01-01	7.1006199999999990
1987-01-01	7.1959700000000000
1988-01-01	7.8483800000000010
1989-01-01	8.1796700000000000
1990-01-01	7.6553300000000000
1991-01-01	5.9731300000000000
1992-01-01	5.1865200000000000
1993-01-01	6.1367199999999995
1994-01-01	6.1367199999999995
1995-01-01	8.4135700000000000
1996-01-01	6.8711699999999990
1997-01-01	6.5478300000000000
1998-01-01	8.2101100000000000
1999-01-01	9.3441000000000000
2000-01-01	9.4972300000000000
2001-01-01	9.7655000000000000
2002-01-01	9.8477800000000000
2003-01-01	8.9326600000000000
2004-01-01	9.3802600000000000
2005-01-01	10.1722000000000000
2006-01-01	10.8492000000000000
2007-01-01	11.5907000000000000
2008-01-01	12.2689000000000000
2009-01-01	11.9561000000000000
2010-01-01	11.0529000000000000
2011-01-01	13.0869000000000000
2012-01-01	16.3035000000000000
2013-01-01	18.0534000000000000
2014-01-01	19.1057000000000000
2015-01-01	20.0315000000000000
2016-01-01	19.7337000000000000