Year	Percent
1960-01-01	5.0422800000000000
1961-01-01	4.7166500000000000
1962-01-01	4.9678500000000000
1963-01-01	5.6981800000000010
1964-01-01	6.3252200000000000
1965-01-01	6.9209300000000000
1966-01-01	7.5946700000000000
1967-01-01	8.6113600000000010
1968-01-01	9.1998699999999990
1969-01-01	10.1026000000000000
1970-01-01	12.4918000000000000
1971-01-01	12.9450000000000000
1972-01-01	11.5675000000000000
1973-01-01	9.7588900000000000
1974-01-01	5.5468400000000000
1975-01-01	4.1391700000000000
1976-01-01	2.8281500000000000
1977-01-01	2.5285300000000000
1978-01-01	2.5285300000000000
1979-01-01	7.1204300000000010
1980-01-01	15.3897000000000000
1981-01-01	29.2116000000000000
1982-01-01	33.1388000000000000
1983-01-01	29.5898000000000000
1984-01-01	29.5898000000000000
1985-01-01	29.5898000000000000
1986-01-01	29.5898000000000000
1987-01-01	29.5898000000000000
1988-01-01	43.3621000000000000
1989-01-01	43.1454000000000000
1990-01-01	33.3123000000000000
1991-01-01	25.1231000000000000
1992-01-01	20.9209000000000000
1993-01-01	14.4670000000000000
1994-01-01	15.3200000000000000
1995-01-01	16.2514000000000000
1996-01-01	13.8219000000000000
1997-01-01	13.3489000000000000
1998-01-01	13.6018000000000000
1999-01-01	12.3691000000000000
2000-01-01	9.6379500000000000
2001-01-01	8.3359399999999990
2002-01-01	8.0675200000000000
2003-01-01	8.5169700000000000
2004-01-01	6.9821300000000010
2005-01-01	5.3316400000000000
2006-01-01	4.4116599999999995
2007-01-01	3.4600900000000000
2008-01-01	2.8620300000000000
2009-01-01	2.4477800000000000
2010-01-01	2.6126400000000003
2011-01-01	2.5695200000000002
2012-01-01	2.2884500000000000
2013-01-01	1.8639000000000000
2014-01-01	1.5885600000000000
2015-01-01	2.0597000000000000
2016-01-01	2.4221900000000000