Year	Percent
1966-01-01	99.89120000000000
1967-01-01	99.89880000000000
1968-01-01	99.89880000000000
1969-01-01	92.28620000000000
1970-01-01	81.25150000000000
1971-01-01	73.15040000000000
1972-01-01	84.74600000000001
1973-01-01	72.59980000000000
1974-01-01	75.78230000000000
1975-01-01	83.77060000000000
1976-01-01	82.57110000000000
1977-01-01	80.50330000000000
1978-01-01	83.77870000000000
1979-01-01	88.37050000000000
1980-01-01	85.67330000000000
1981-01-01	83.08500000000000
1982-01-01	83.18410000000000
1983-01-01	84.07580000000000
1984-01-01	86.62299999999999
1985-01-01	87.63410000000000
1986-01-01	87.17190000000000
1987-01-01	84.69270000000000
1988-01-01	77.57700000000000
1989-01-01	72.55450000000000
1990-01-01	72.94430000000000
1991-01-01	75.15980000000000
1992-01-01	77.38910000000000
1993-01-01	79.65560000000000
1994-01-01	81.16950000000000
1995-01-01	83.16850000000000
1996-01-01	85.28350000000000
1997-01-01	85.78780000000000
1998-01-01	86.51450000000000
1999-01-01	87.72250000000000
2000-01-01	87.72600000000000
2001-01-01	87.73790000000000
2002-01-01	89.41520000000000
2003-01-01	90.60520000000000
2004-01-01	91.48600000000000
2005-01-01	91.78800000000000
2006-01-01	93.31120000000000
2007-01-01	95.36510000000000
2008-01-01	94.34170000000000
2009-01-01	93.37350000000000
2010-01-01	94.13600000000001
2011-01-01	94.68220000000000
2012-01-01	93.50560000000000
2013-01-01	93.36570000000000
2014-01-01	95.19440000000000
2015-01-01	96.38130000000000
2016-01-01	96.88720000000000