Year	Percent
1960-01-01	60.314600000000000
1961-01-01	61.641900000000000
1962-01-01	61.142800000000000
1963-01-01	56.905200000000000
1964-01-01	54.036000000000000
1965-01-01	49.689400000000000
1966-01-01	40.970900000000000
1967-01-01	38.709800000000000
1968-01-01	40.696999999999996
1969-01-01	41.019800000000000
1970-01-01	40.495800000000000
1971-01-01	36.433600000000000
1972-01-01	34.213600000000000
1973-01-01	35.904400000000000
1974-01-01	34.167000000000000
1975-01-01	56.761200000000000
1976-01-01	76.751000000000000
1977-01-01	79.266300000000000
1978-01-01	84.532000000000010
1979-01-01	88.333700000000000
1980-01-01	89.914000000000000
1981-01-01	90.854800000000000
1982-01-01	87.796900000000000
1983-01-01	74.211300000000000
1984-01-01	57.486900000000000
1985-01-01	55.450200000000000
1986-01-01	52.520100000000000
1987-01-01	44.312600000000000
1988-01-01	44.004800000000000
1989-01-01	51.262100000000000
1990-01-01	57.041900000000000
1991-01-01	60.688100000000000
1992-01-01	63.781400000000000
1993-01-01	64.548300000000000
1994-01-01	67.036100000000000
1995-01-01	69.304500000000000
1996-01-01	71.395400000000000
1997-01-01	73.953500000000000
1998-01-01	77.038600000000000
1999-01-01	77.783300000000000
2000-01-01	76.072400000000000
2001-01-01	80.928300000000000
2002-01-01	76.047600000000000
2003-01-01	65.991000000000000
2004-01-01	60.135600000000000
2005-01-01	58.539700000000000
2006-01-01	68.427700000000000
2007-01-01	78.983600000000000
2008-01-01	77.463900000000000
2009-01-01	74.903500000000000
2010-01-01	73.266800000000000
2011-01-01	73.663100000000000
2012-01-01	74.319400000000000
2013-01-01	73.307300000000000
2014-01-01	74.087500000000000
2015-01-01	76.264100000000000
2016-01-01	77.069600000000000