Year	Percent
1965-01-01	96.558500000000000
1966-01-01	92.973600000000000
1967-01-01	92.059400000000000
1968-01-01	89.731300000000000
1969-01-01	84.871100000000000
1970-01-01	88.009000000000000
1971-01-01	94.081100000000000
1972-01-01	90.932999999999990
1973-01-01	87.184000000000000
1974-01-01	88.461000000000000
1975-01-01	72.816200000000000
1976-01-01	65.586600000000000
1977-01-01	71.674300000000000
1978-01-01	76.829600000000000
1979-01-01	75.234400000000000
1980-01-01	73.352000000000000
1981-01-01	63.392400000000000
1982-01-01	54.341000000000000
1983-01-01	50.980800000000000
1984-01-01	52.542100000000000
1985-01-01	53.157900000000000
1986-01-01	48.259100000000000
1987-01-01	42.418300000000000
1988-01-01	40.465400000000000
1989-01-01	44.938900000000000
1990-01-01	50.428600000000000
1991-01-01	56.620000000000000
1992-01-01	55.651300000000000
1993-01-01	53.644200000000000
1994-01-01	53.508200000000000
1995-01-01	56.877800000000000
1996-01-01	71.826900000000000
1997-01-01	77.968800000000000
1998-01-01	64.281900000000000
1999-01-01	62.411100000000000
2000-01-01	79.969700000000000
2001-01-01	74.530100000000000
2002-01-01	55.871000000000000
2003-01-01	55.892100000000000
2004-01-01	57.780700000000000
2005-01-01	56.821999999999996
2006-01-01	65.337800000000000
2007-01-01	72.455300000000000
2008-01-01	59.408700000000000
2009-01-01	53.944500000000000
2010-01-01	58.986700000000000
2011-01-01	62.999400000000000
2012-01-01	64.347000000000000
2013-01-01	65.347500000000000
2014-01-01	70.263300000000000
2015-01-01	75.364500000000000
2016-01-01	63.024200000000000