Year	Percent
1960-01-01	76.27630000000000
1961-01-01	76.28540000000000
1962-01-01	72.83850000000000
1963-01-01	72.11250000000000
1964-01-01	74.10200000000000
1965-01-01	71.42990000000000
1966-01-01	68.83330000000000
1967-01-01	69.23910000000000
1968-01-01	72.09210000000000
1969-01-01	74.37480000000000
1970-01-01	75.96400000000000
1971-01-01	78.11960000000000
1972-01-01	79.41280000000000
1973-01-01	81.16840000000000
1974-01-01	87.76700000000001
1975-01-01	90.31010000000000
1976-01-01	91.41830000000000
1977-01-01	93.71620000000000
1978-01-01	94.69620000000000
1979-01-01	95.22390000000000
1980-01-01	95.97160000000000
1981-01-01	96.67660000000000
1982-01-01	95.38700000000000
1983-01-01	92.16490000000000
1984-01-01	87.75480000000000
1985-01-01	84.56720000000000
1986-01-01	84.56720000000000
1987-01-01	79.77890000000000
1988-01-01	79.68590000000000
1989-01-01	79.68590000000000
1990-01-01	88.82560000000000
1991-01-01	90.80630000000000
1992-01-01	92.83480000000000
1993-01-01	95.00790000000000
1994-01-01	96.55070000000000
1995-01-01	97.52270000000000
1996-01-01	98.01780000000000
1997-01-01	98.33790000000000
1998-01-01	98.10010000000000
1999-01-01	96.38290000000000
2000-01-01	94.92430000000000
2001-01-01	95.94810000000000
2002-01-01	96.67650000000000
2003-01-01	96.12100000000001
2004-01-01	97.57050000000000
2005-01-01	98.29240000000000
2006-01-01	97.97280000000000
2007-01-01	98.67840000000000
2008-01-01	99.29340000000000
2009-01-01	98.77340000000000
2010-01-01	98.73910000000000
2011-01-01	99.41980000000000
2012-01-01	99.57740000000000
2013-01-01	99.78000000000000
2014-01-01	99.92190000000000
2015-01-01	99.93730000000000
2016-01-01	98.99830000000000