Year	Percent
1965-01-01	57.471600000000000
1966-01-01	55.982900000000000
1967-01-01	54.358500000000000
1968-01-01	55.320200000000000
1969-01-01	55.402900000000000
1970-01-01	47.092000000000000
1971-01-01	45.878000000000000
1972-01-01	47.454200000000000
1973-01-01	51.010300000000000
1974-01-01	51.130100000000000
1975-01-01	52.127400000000000
1976-01-01	52.395400000000000
1977-01-01	51.745800000000000
1978-01-01	50.821999999999996
1979-01-01	49.615600000000000
1980-01-01	44.423500000000000
1981-01-01	45.971400000000000
1982-01-01	47.107400000000000
1983-01-01	47.017300000000000
1984-01-01	46.799000000000000
1985-01-01	47.793600000000000
1986-01-01	45.611900000000000
1987-01-01	44.230600000000000
1988-01-01	45.148500000000000
1989-01-01	46.793800000000000
1990-01-01	46.775700000000000
1991-01-01	46.775700000000000
1992-01-01	44.388700000000000
1993-01-01	42.054300000000000
1994-01-01	41.655300000000000
1995-01-01	43.179100000000000
1996-01-01	43.853200000000000
1997-01-01	46.461500000000000
1998-01-01	49.499100000000000
1999-01-01	50.565900000000000
2000-01-01	48.861100000000000
2001-01-01	49.587600000000000
2002-01-01	47.925000000000000
2003-01-01	48.949700000000000
2004-01-01	48.418500000000000
2005-01-01	49.900500000000000
2006-01-01	53.659000000000000
2007-01-01	56.639800000000000
2008-01-01	60.394800000000000
2009-01-01	61.090500000000000
2010-01-01	57.367000000000000
2011-01-01	57.894600000000000
2012-01-01	59.031500000000000
2013-01-01	57.853000000000000
2014-01-01	58.316100000000000
2015-01-01	59.515800000000000
2016-01-01	59.542200000000000