Year	Percent
1960-01-01	51.191500000000000
1961-01-01	50.427300000000000
1962-01-01	49.973000000000000
1963-01-01	49.101600000000000
1964-01-01	48.529900000000000
1965-01-01	47.358400000000000
1966-01-01	52.765600000000000
1967-01-01	52.685500000000000
1968-01-01	54.512400000000000
1969-01-01	55.580500000000000
1970-01-01	48.722500000000000
1971-01-01	48.387600000000000
1972-01-01	49.607100000000000
1973-01-01	49.138700000000000
1974-01-01	47.790600000000000
1975-01-01	47.771300000000000
1976-01-01	46.602200000000000
1977-01-01	46.841300000000000
1978-01-01	48.204100000000000
1979-01-01	48.397100000000000
1980-01-01	46.684700000000000
1981-01-01	45.934900000000000
1982-01-01	46.295100000000000
1983-01-01	45.751800000000000
1984-01-01	46.602400000000000
1985-01-01	49.055700000000000
1986-01-01	51.489200000000000
1987-01-01	52.585800000000000
1988-01-01	56.232600000000000
1989-01-01	56.024100000000000
1990-01-01	56.584700000000000
1991-01-01	55.917800000000000
1992-01-01	57.339000000000000
1993-01-01	56.687100000000000
1994-01-01	54.936400000000000
1995-01-01	53.677700000000000
1996-01-01	51.301700000000000
1997-01-01	49.604500000000000
1998-01-01	52.711000000000006
1999-01-01	52.284800000000000
2000-01-01	46.248000000000005
2001-01-01	47.298200000000000
2002-01-01	49.497200000000000
2003-01-01	50.937500000000000
2004-01-01	48.756100000000000
2005-01-01	47.887200000000000
2006-01-01	47.641000000000005
2007-01-01	49.358700000000000
2008-01-01	49.239300000000000
2009-01-01	54.678200000000000
2010-01-01	53.301700000000000
2011-01-01	52.590500000000000
2012-01-01	51.943500000000000
2013-01-01	52.957000000000000
2014-01-01	55.431200000000000
2015-01-01	59.140300000000000
2016-01-01	62.717700000000000