Year	Percent
1960-01-01	50.370500000000000
1961-01-01	55.784100000000000
1962-01-01	61.464300000000000
1963-01-01	60.700600000000000
1964-01-01	59.283900000000000
1965-01-01	59.301900000000000
1966-01-01	60.388600000000000
1967-01-01	62.402400000000000
1968-01-01	63.621400000000000
1969-01-01	63.760200000000000
1970-01-01	64.261500000000000
1971-01-01	64.576300000000000
1972-01-01	63.662800000000000
1973-01-01	60.525900000000000
1974-01-01	59.533300000000000
1975-01-01	60.150500000000000
1976-01-01	61.795100000000000
1977-01-01	63.888300000000000
1978-01-01	55.802000000000000
1979-01-01	46.894800000000000
1980-01-01	48.739700000000000
1981-01-01	52.238000000000000
1982-01-01	51.482700000000000
1983-01-01	51.276900000000000
1984-01-01	52.740200000000000
1985-01-01	55.417400000000000
1986-01-01	57.788300000000000
1987-01-01	59.113600000000000
1988-01-01	59.563100000000000
1989-01-01	57.994300000000000
1990-01-01	52.963200000000000
1991-01-01	52.860500000000000
1992-01-01	58.943000000000005
1993-01-01	64.450100000000000
1994-01-01	68.343500000000000
1995-01-01	71.539100000000000
1996-01-01	75.526600000000000
1997-01-01	79.748400000000000
1998-01-01	79.632500000000000
1999-01-01	76.961600000000000
2000-01-01	74.442700000000000
2001-01-01	72.167100000000000
2002-01-01	71.356300000000000
2003-01-01	69.001600000000000
2004-01-01	64.703400000000000
2005-01-01	66.072200000000000
2006-01-01	70.118600000000000
2007-01-01	71.130100000000000
2008-01-01	76.018900000000000
2009-01-01	80.810100000000000
2010-01-01	81.522500000000000
2011-01-01	81.143200000000000
2012-01-01	79.323000000000010
2013-01-01	76.597400000000000
2014-01-01	73.759500000000000
2015-01-01	72.591000000000010
2016-01-01	75.370200000000000