Year	Percent
1960-01-01	52.332700000000000
1961-01-01	50.131200000000000
1962-01-01	50.593700000000000
1963-01-01	51.331700000000000
1964-01-01	49.706300000000000
1965-01-01	48.325900000000000
1966-01-01	48.414300000000000
1967-01-01	49.852500000000000
1968-01-01	52.759200000000000
1969-01-01	52.746600000000000
1970-01-01	49.795300000000000
1971-01-01	49.643600000000000
1972-01-01	50.318900000000000
1973-01-01	51.392300000000000
1974-01-01	51.038400000000000
1975-01-01	47.698400000000000
1976-01-01	45.904600000000000
1977-01-01	45.123100000000000
1978-01-01	45.871200000000000
1979-01-01	47.626700000000000
1980-01-01	46.946400000000000
1981-01-01	48.931000000000004
1982-01-01	49.283000000000000
1983-01-01	46.150000000000000
1984-01-01	43.686700000000000
1985-01-01	43.149300000000000
1986-01-01	42.943200000000000
1987-01-01	43.412400000000000
1988-01-01	42.518700000000000
1989-01-01	42.010700000000000
1990-01-01	42.010700000000000
1991-01-01	42.010700000000000
1992-01-01	42.010700000000000
1993-01-01	42.010700000000000
1994-01-01	42.010700000000000
1995-01-01	42.010700000000000
1996-01-01	42.010700000000000
1997-01-01	42.010700000000000
1998-01-01	42.010700000000000
1999-01-01	42.010700000000000
2000-01-01	42.010700000000000
2001-01-01	40.116800000000000
2002-01-01	39.930500000000000
2003-01-01	40.081800000000000
2004-01-01	39.423000000000000
2005-01-01	40.966200000000000
2006-01-01	43.437500000000000
2007-01-01	45.773200000000000
2008-01-01	50.307100000000000
2009-01-01	55.276200000000000
2010-01-01	55.085600000000000
2011-01-01	57.689800000000000
2012-01-01	60.145300000000000
2013-01-01	61.455500000000000
2014-01-01	62.515500000000000
2015-01-01	62.723400000000000
2016-01-01	64.896300000000000