Year	Percent
1964-01-01	99.9853
1965-01-01	99.9858
1966-01-01	99.9852
1967-01-01	99.9285
1968-01-01	99.9506
1969-01-01	99.9857
1970-01-01	99.9874
1971-01-01	99.9866
1972-01-01	99.9928
1973-01-01	99.9940
1974-01-01	99.9993
1975-01-01	99.8038
1976-01-01	98.5075
1977-01-01	96.2228
1978-01-01	95.6666
1979-01-01	94.8466
1980-01-01	90.9278
1981-01-01	86.6576
1982-01-01	80.3638
1983-01-01	75.1046
1984-01-01	73.4669
1985-01-01	72.4199
1986-01-01	71.6242
1987-01-01	71.0716
1988-01-01	71.8105
1989-01-01	72.6083
1990-01-01	72.4561
1991-01-01	72.1784
1992-01-01	72.5377
1993-01-01	73.5031
1994-01-01	68.0747
1995-01-01	60.5730
1996-01-01	65.3688
1997-01-01	67.1375
1998-01-01	65.0323
1999-01-01	66.7086
2000-01-01	70.9158
2001-01-01	72.9545
2002-01-01	72.3610
2003-01-01	74.9044
2004-01-01	79.0479
2005-01-01	83.3050
2006-01-01	88.6991
2007-01-01	92.7792
2008-01-01	93.4754
2009-01-01	90.8119
2010-01-01	88.7353
2011-01-01	89.7105
2012-01-01	91.2871
2013-01-01	92.7259
2014-01-01	93.9932
2015-01-01	95.2496
2016-01-01	96.6400