Year	Percent
1980-01-01	99.998400000000000
1981-01-01	89.212200000000000
1982-01-01	81.013400000000000
1983-01-01	83.654100000000000
1984-01-01	91.678300000000000
1985-01-01	91.509100000000000
1986-01-01	86.519700000000000
1987-01-01	80.083100000000000
1988-01-01	62.989700000000000
1989-01-01	56.388999999999996
1990-01-01	58.392100000000000
1991-01-01	50.806200000000000
1992-01-01	56.176000000000000
1993-01-01	74.083500000000000
1994-01-01	74.170500000000000
1995-01-01	75.379500000000000
1996-01-01	72.895900000000000
1997-01-01	86.749500000000000
1998-01-01	87.465200000000000
1999-01-01	90.206300000000000
2000-01-01	92.562600000000000
2001-01-01	89.591700000000000
2002-01-01	88.137999999999990
2003-01-01	89.498900000000000
2004-01-01	86.079000000000000
2005-01-01	83.213700000000000
2006-01-01	84.069500000000000
2007-01-01	85.242600000000000
2008-01-01	81.711100000000000
2009-01-01	85.273600000000000
2010-01-01	93.973300000000000
2011-01-01	93.282900000000000
2012-01-01	90.914300000000000
2013-01-01	87.433200000000000
2014-01-01	85.779200000000000
2015-01-01	85.330200000000000
2016-01-01	84.486700000000000