Year	Percent
1960-01-01	34.770600000000000
1961-01-01	35.491100000000000
1962-01-01	37.773900000000000
1963-01-01	29.457600000000000
1964-01-01	11.070900000000000
1965-01-01	9.379040000000000
1966-01-01	11.443800000000000
1967-01-01	9.177030000000000
1968-01-01	9.818980000000000
1969-01-01	10.976200000000000
1970-01-01	14.948000000000000
1971-01-01	16.880300000000000
1972-01-01	20.825500000000000
1973-01-01	26.592000000000000
1974-01-01	27.008500000000000
1975-01-01	26.204700000000000
1976-01-01	23.965200000000000
1977-01-01	27.434400000000000
1978-01-01	46.601600000000000
1979-01-01	64.832200000000000
1980-01-01	82.111700000000000
1981-01-01	95.793200000000000
1982-01-01	99.994400000000000
1983-01-01	99.995600000000000
1984-01-01	99.998100000000000
1985-01-01	99.998100000000000
1986-01-01	99.998100000000000
1987-01-01	99.998100000000000
1988-01-01	99.998100000000000
1989-01-01	58.931900000000000
1990-01-01	11.293600000000000
1991-01-01	17.663600000000000
1992-01-01	22.922300000000000
1993-01-01	24.409400000000000
1994-01-01	25.022300000000000
1995-01-01	26.593300000000000
1996-01-01	29.923500000000000
1997-01-01	34.615700000000000
1998-01-01	39.498500000000000
1999-01-01	41.483800000000000
2000-01-01	41.093100000000000
2001-01-01	43.677600000000000
2002-01-01	46.070600000000000
2003-01-01	37.075200000000000
2004-01-01	26.171300000000000
2005-01-01	24.404500000000000
2006-01-01	22.635900000000000
2007-01-01	21.870800000000000
2008-01-01	24.348000000000003
2009-01-01	29.040600000000000
2010-01-01	40.295000000000000
2011-01-01	48.456400000000000
2012-01-01	57.233400000000000
2013-01-01	68.040900000000000
2014-01-01	75.220600000000000
2015-01-01	75.758600000000000
2016-01-01	74.251800000000000