Year	Percent
1960-01-01	6.2941400000000005
1961-01-01	6.3981699999999995
1962-01-01	6.7466899999999990
1963-01-01	6.3464000000000000
1964-01-01	6.4239400000000000
1965-01-01	6.8692600000000010
1966-01-01	8.6308600000000000
1967-01-01	9.6873600000000000
1968-01-01	10.1100000000000000
1969-01-01	10.1899000000000000
1970-01-01	7.7620000000000005
1971-01-01	7.7172600000000005
1972-01-01	8.4453400000000000
1973-01-01	10.3804000000000000
1974-01-01	11.2938000000000000
1975-01-01	10.0709000000000000
1976-01-01	10.3028000000000000
1977-01-01	6.5382700000000000
1978-01-01	5.9638100000000000
1979-01-01	5.0978900000000005
1980-01-01	5.4655100000000000
1981-01-01	6.0508500000000000
1982-01-01	5.2957900000000000
1983-01-01	4.4714000000000000
1984-01-01	3.7395400000000003
1985-01-01	4.0251500000000000
1986-01-01	4.4215900000000000
1987-01-01	3.9110099999999997
1988-01-01	2.7494099999999997
1989-01-01	2.6151900000000000
1990-01-01	3.6532699999999996
1991-01-01	4.0031000000000000
1992-01-01	5.0779300000000000
1993-01-01	5.4316900000000010
1994-01-01	7.1400000000000000
1995-01-01	7.3622200000000000
1996-01-01	7.8602600000000000
1997-01-01	8.6587800000000000
1998-01-01	9.3689900000000000
1999-01-01	10.1612000000000000
2000-01-01	10.3375000000000000
2001-01-01	11.2976000000000000
2002-01-01	12.0265000000000000
2003-01-01	13.3161000000000000
2004-01-01	12.8887000000000000
2005-01-01	13.0715000000000000
2006-01-01	12.9643000000000000
2007-01-01	13.0137000000000000
2008-01-01	13.3837000000000000
2009-01-01	13.3983000000000000
2010-01-01	14.6153000000000000
2011-01-01	15.3475000000000000
2012-01-01	15.0882000000000000
2013-01-01	15.7179000000000000
2014-01-01	16.1860000000000000
2015-01-01	16.2532000000000000
2016-01-01	16.8525000000000000