Year	Percent
1970-01-01	0.43702200000000000
1971-01-01	0.39001600000000000
1972-01-01	0.44069200000000003
1973-01-01	0.44028000000000000
1974-01-01	0.34766600000000000
1975-01-01	0.29503000000000000
1976-01-01	0.29102400000000000
1977-01-01	0.29638900000000000
1978-01-01	0.35131900000000000
1979-01-01	0.36813200000000000
1980-01-01	0.42179799999999995
1981-01-01	0.41943100000000005
1982-01-01	0.39806600000000000
1983-01-01	0.50866800000000000
1984-01-01	0.49490300000000000
1985-01-01	0.55997800000000000
1986-01-01	0.57883500000000000
1987-01-01	0.73860500000000010
1988-01-01	0.79962000000000000
1989-01-01	0.80257900000000000
1990-01-01	0.76232100000000000
1991-01-01	0.76374900000000000
1992-01-01	0.59286600000000000
1993-01-01	0.35369700000000000
1994-01-01	0.39632600000000000
1995-01-01	0.11951800000000001
1996-01-01	0.12937600000000000
1997-01-01	0.12397300000000000
1998-01-01	0.12574200000000002
1999-01-01	0.13692600000000000
2000-01-01	0.12488900000000001
2001-01-01	0.12869500000000000
2002-01-01	0.11805800000000000
2003-01-01	0.13973400000000000
2004-01-01	0.13478099999999998
2005-01-01	0.13577100000000000
2006-01-01	0.13612500000000000
2007-01-01	0.15750100000000000
2008-01-01	0.14497900000000000
2009-01-01	0.14406100000000000
2010-01-01	0.16294100000000000
2011-01-01	0.17566700000000002
2012-01-01	0.15584400000000000
2013-01-01	0.15183300000000000
2014-01-01	0.15415800000000000
2015-01-01	0.15871800000000000
2016-01-01	0.17014200000000002
2017-01-01	0.15163200000000000