Year	Percent
1960-01-01	38.633400000000000
1961-01-01	39.118200000000000
1962-01-01	40.187500000000000
1963-01-01	42.701000000000000
1964-01-01	44.647400000000000
1965-01-01	46.265500000000000
1966-01-01	46.638100000000000
1967-01-01	47.180400000000000
1968-01-01	47.017400000000000
1969-01-01	47.607800000000000
1970-01-01	48.367400000000000
1971-01-01	48.140400000000000
1972-01-01	49.891800000000000
1973-01-01	52.288999999999994
1974-01-01	54.925400000000000
1975-01-01	53.389300000000000
1976-01-01	51.126999999999995
1977-01-01	52.247400000000000
1978-01-01	53.053400000000000
1979-01-01	53.858600000000000
1980-01-01	54.165300000000000
1981-01-01	51.061800000000000
1982-01-01	51.087400000000000
1983-01-01	49.427900000000000
1984-01-01	50.189300000000000
1985-01-01	52.431999999999995
1986-01-01	54.160500000000000
1987-01-01	55.328600000000000
1988-01-01	54.977000000000000
1989-01-01	54.804100000000000
1990-01-01	53.101800000000000
1991-01-01	50.091200000000000
1992-01-01	46.018700000000000
1993-01-01	43.936600000000000
1994-01-01	43.115500000000000
1995-01-01	44.201400000000000
1996-01-01	44.889900000000000
1997-01-01	45.052000000000000
1998-01-01	45.641500000000000
1999-01-01	45.864600000000000
2000-01-01	46.817200000000000
2001-01-01	49.092900000000000
2002-01-01	49.537300000000000
2003-01-01	49.880600000000000
2004-01-01	50.998500000000000
2005-01-01	52.909800000000000
2006-01-01	55.150900000000000
2007-01-01	57.439800000000000
2008-01-01	60.744400000000000
2009-01-01	57.605700000000000
2010-01-01	51.550400000000000
2011-01-01	50.408200000000000
2012-01-01	49.092800000000000
2013-01-01	48.894500000000000
2014-01-01	49.168400000000000
2015-01-01	50.156000000000006
2016-01-01	51.807400000000000