Year	Percent
1960-01-01	77.50000000000000
1961-01-01	78.57530000000000
1962-01-01	80.42230000000000
1963-01-01	81.87600000000000
1964-01-01	82.96770000000000
1965-01-01	84.25590000000000
1966-01-01	85.62440000000000
1967-01-01	87.80720000000000
1968-01-01	88.37450000000000
1969-01-01	88.11750000000000
1970-01-01	89.41710000000000
1971-01-01	91.34430000000000
1972-01-01	93.42100000000000
1973-01-01	94.26390000000000
1974-01-01	94.39270000000000
1975-01-01	94.89570000000000
1976-01-01	94.83050000000000
1977-01-01	94.04980000000000
1978-01-01	94.03280000000000
1979-01-01	94.71790000000000
1980-01-01	93.05720000000000
1981-01-01	89.99760000000000
1982-01-01	88.69400000000000
1983-01-01	89.14050000000000
1984-01-01	89.86640000000000
1985-01-01	90.67710000000000
1986-01-01	91.22740000000000
1987-01-01	92.48000000000000
1988-01-01	94.22690000000000
1989-01-01	95.43640000000000
1990-01-01	96.48640000000000
1991-01-01	97.73480000000000
1992-01-01	99.12630000000000
1993-01-01	99.27970000000000
1994-01-01	99.27990000000000
1995-01-01	99.32590000000000
1996-01-01	99.29630000000000
1997-01-01	99.28450000000000
1998-01-01	99.28450000000000
1999-01-01	99.65670000000000
2000-01-01	99.61480000000000
2001-01-01	99.59660000000000
2002-01-01	99.65190000000000
2003-01-01	99.73210000000000
2004-01-01	99.75340000000000
2005-01-01	99.72750000000000
2006-01-01	99.71760000000000
2007-01-01	99.52370000000000
2008-01-01	99.21540000000000
2009-01-01	99.09299999999999
2010-01-01	98.93940000000000
2011-01-01	98.66220000000000
2012-01-01	98.41690000000000
2013-01-01	98.35110000000000
2014-01-01	98.49460000000000
2015-01-01	96.57380000000000
2016-01-01	91.69790000000000