Year	Percent
1960-01-01	61.928100000000000
1961-01-01	66.333400000000000
1962-01-01	69.537300000000000
1963-01-01	64.378300000000000
1964-01-01	46.521700000000000
1965-01-01	34.772200000000000
1966-01-01	26.917100000000000
1967-01-01	24.371100000000000
1968-01-01	28.278000000000002
1969-01-01	39.240500000000000
1970-01-01	54.495500000000000
1971-01-01	63.846100000000000
1972-01-01	70.161400000000000
1973-01-01	83.648700000000000
1974-01-01	76.616300000000000
1975-01-01	70.645800000000000
1976-01-01	100.684000000000000
1977-01-01	138.647000000000020
1978-01-01	154.889000000000000
1979-01-01	123.914000000000000
1980-01-01	87.696200000000000
1981-01-01	75.207700000000000
1982-01-01	62.301800000000000
1983-01-01	51.052700000000000
1984-01-01	41.561500000000000
1985-01-01	36.169700000000000
1986-01-01	35.776700000000000
1987-01-01	33.129100000000000
1988-01-01	31.694900000000000
1989-01-01	31.209100000000000
1990-01-01	41.779300000000000
1991-01-01	60.556000000000004
1992-01-01	73.172900000000000
1993-01-01	77.583800000000000
1994-01-01	70.423400000000000
1995-01-01	66.887500000000000
1996-01-01	71.138400000000000
1997-01-01	81.287600000000000
1998-01-01	83.332900000000000
1999-01-01	68.457600000000000
2000-01-01	55.902000000000000
2001-01-01	56.017800000000000
2002-01-01	63.511800000000000
2003-01-01	68.143300000000000
2004-01-01	61.889800000000000
2005-01-01	60.945700000000000
2006-01-01	58.190300000000000
2007-01-01	50.318200000000000
2008-01-01	45.176300000000000
2009-01-01	40.785300000000000
2010-01-01	37.938500000000000
2011-01-01	41.105400000000000
2012-01-01	45.123999999999995
2013-01-01	49.292800000000000
2014-01-01	53.958700000000000
2015-01-01	54.846600000000000
2016-01-01	56.409900000000000