Year	Percent
1960-01-01	1.7764500000000000
1961-01-01	1.7467700000000002
1962-01-01	2.1672100000000000
1963-01-01	2.1672100000000000
1964-01-01	2.1672100000000000
1965-01-01	2.1672100000000000
1966-01-01	2.1672100000000000
1967-01-01	3.3128200000000000
1968-01-01	3.4680900000000000
1969-01-01	3.9614100000000000
1970-01-01	3.6730400000000003
1971-01-01	4.4111100000000000
1972-01-01	5.2866400000000000
1973-01-01	6.4536800000000000
1974-01-01	7.2723300000000000
1975-01-01	6.6529399999999990
1976-01-01	5.7365800000000000
1977-01-01	6.5181500000000000
1978-01-01	7.6801800000000000
1979-01-01	8.0609200000000000
1980-01-01	7.7643400000000000
1981-01-01	9.0308100000000000
1982-01-01	8.2150199999999990
1983-01-01	6.9126500000000000
1984-01-01	9.5598800000000000
1985-01-01	11.4422000000000000
1986-01-01	12.2486000000000000
1987-01-01	11.7553000000000000
1988-01-01	12.4053000000000000
1989-01-01	13.2856000000000000
1990-01-01	14.1135000000000000
1991-01-01	12.5998000000000000
1992-01-01	12.5022000000000000
1993-01-01	12.0084000000000000
1994-01-01	9.7453899999999990
1995-01-01	8.6834899999999990
1996-01-01	7.2784400000000000
1997-01-01	5.9736100000000000
1998-01-01	4.6867800000000010
1999-01-01	4.6549800000000000
2000-01-01	5.4386600000000000
2001-01-01	5.9036700000000000
2002-01-01	6.3550600000000000
2003-01-01	6.5804399999999990
2004-01-01	7.7486700000000000
2005-01-01	7.8534800000000000
2006-01-01	7.7327699999999995
2007-01-01	8.9780400000000000
2008-01-01	9.7664000000000000
2009-01-01	10.1631000000000000
2010-01-01	10.8392000000000000
2011-01-01	11.1510000000000000
2012-01-01	11.0384000000000000
2013-01-01	12.3609999999999990
2014-01-01	13.1850000000000000
2015-01-01	14.1190000000000020
2016-01-01	13.7382000000000000