Year	Percent
1963-01-01	99.444500000000000
1964-01-01	97.097400000000000
1965-01-01	95.016900000000000
1966-01-01	93.955200000000000
1967-01-01	92.032300000000000
1968-01-01	91.340300000000000
1969-01-01	89.966600000000000
1970-01-01	84.802800000000000
1971-01-01	81.447800000000000
1972-01-01	81.293700000000000
1973-01-01	79.502600000000000
1974-01-01	80.597900000000000
1975-01-01	85.066800000000000
1976-01-01	83.777999999999990
1977-01-01	80.176500000000000
1978-01-01	81.263400000000000
1979-01-01	80.948500000000000
1980-01-01	80.043900000000000
1981-01-01	77.724500000000000
1982-01-01	75.587900000000000
1983-01-01	77.428500000000000
1984-01-01	81.969600000000000
1985-01-01	85.635200000000000
1986-01-01	88.525800000000000
1987-01-01	87.718700000000000
1988-01-01	86.349100000000000
1989-01-01	84.249600000000000
1990-01-01	80.314100000000000
1991-01-01	79.992400000000000
1992-01-01	71.168600000000000
1993-01-01	56.523900000000000
1994-01-01	47.452600000000000
1995-01-01	45.499800000000000
1996-01-01	45.403600000000000
1997-01-01	44.403200000000000
1998-01-01	45.356300000000000
1999-01-01	43.331900000000000
2000-01-01	39.671600000000000
2001-01-01	40.416000000000000
2002-01-01	43.463000000000000
2003-01-01	49.897800000000000
2004-01-01	53.059300000000000
2005-01-01	53.556999999999995
2006-01-01	61.490300000000000
2007-01-01	67.131300000000000
2008-01-01	68.981800000000000
2009-01-01	62.301700000000000
2010-01-01	54.381600000000000
2011-01-01	55.878200000000000
2012-01-01	59.208900000000000
2013-01-01	62.146300000000000
2014-01-01	67.758400000000000
2015-01-01	64.012900000000000