Year	Percent
1960-01-01	35.047200000000000
1961-01-01	35.001700000000000
1962-01-01	36.292200000000000
1963-01-01	37.511600000000000
1964-01-01	38.112700000000000
1965-01-01	37.173300000000000
1966-01-01	35.993000000000000
1967-01-01	35.742100000000000
1968-01-01	36.126999999999995
1969-01-01	36.001999999999995
1970-01-01	29.722100000000000
1971-01-01	28.720800000000000
1972-01-01	29.443700000000000
1973-01-01	34.118200000000000
1974-01-01	37.424800000000000
1975-01-01	37.252100000000000
1976-01-01	39.056700000000000
1977-01-01	42.191700000000000
1978-01-01	45.942700000000000
1979-01-01	46.221000000000004
1980-01-01	54.844400000000000
1981-01-01	67.524100000000000
1982-01-01	76.156000000000000
1983-01-01	78.833500000000000
1984-01-01	83.818300000000000
1985-01-01	82.829900000000000
1986-01-01	92.836900000000000
1987-01-01	77.957700000000000
1988-01-01	79.012900000000000
1989-01-01	73.474500000000000
1990-01-01	72.073300000000000
1991-01-01	79.351600000000000
1992-01-01	73.406900000000000
1993-01-01	77.306300000000000
1994-01-01	75.976800000000000
1995-01-01	74.102000000000000
1996-01-01	71.411800000000000
1997-01-01	70.480600000000000
1998-01-01	69.997300000000000
1999-01-01	70.513700000000000
2000-01-01	69.282700000000000
2001-01-01	73.792900000000000
2002-01-01	78.894100000000000
2003-01-01	83.654300000000000
2004-01-01	87.163400000000000
2005-01-01	87.529500000000000
2006-01-01	86.311300000000000
2007-01-01	83.745000000000000
2008-01-01	84.054800000000000
2009-01-01	76.641800000000000
2010-01-01	72.875400000000000
2011-01-01	70.315800000000000
2012-01-01	66.345800000000000
2013-01-01	69.845700000000000
2014-01-01	71.070900000000000
2015-01-01	72.453400000000000
2016-01-01	81.910200000000000