Year	Percent
1960-01-01	19.649400000000000
1961-01-01	18.473900000000000
1962-01-01	19.880300000000000
1963-01-01	22.990300000000000
1964-01-01	23.713600000000000
1965-01-01	24.030900000000000
1966-01-01	23.451200000000000
1967-01-01	24.926900000000000
1968-01-01	28.134800000000000
1969-01-01	31.251800000000000
1970-01-01	32.161600000000000
1971-01-01	34.299500000000000
1972-01-01	35.644000000000000
1973-01-01	35.354700000000000
1974-01-01	34.375000000000000
1975-01-01	35.260300000000000
1976-01-01	36.310100000000000
1977-01-01	36.422000000000000
1978-01-01	34.295300000000000
1979-01-01	35.248500000000000
1980-01-01	40.073400000000000
1981-01-01	44.258200000000000
1982-01-01	49.566300000000000
1983-01-01	52.730300000000000
1984-01-01	50.593100000000000
1985-01-01	50.347500000000000
1986-01-01	60.618700000000000
1987-01-01	68.280100000000000
1988-01-01	73.429900000000000
1989-01-01	76.009100000000000
1990-01-01	54.517100000000000
1991-01-01	46.897600000000000
1992-01-01	40.934400000000000
1993-01-01	37.850700000000000
1994-01-01	38.688700000000000
1995-01-01	37.363700000000000
1996-01-01	43.295200000000000
1997-01-01	46.100500000000000
1998-01-01	47.917900000000000
1999-01-01	48.009300000000000
2000-01-01	44.020200000000000
2001-01-01	46.251800000000000
2002-01-01	49.771700000000000
2003-01-01	46.276900000000000
2004-01-01	45.423800000000000
2005-01-01	46.205900000000000
2006-01-01	45.922200000000000
2007-01-01	43.847100000000000
2008-01-01	44.403999999999996
2009-01-01	46.896500000000000
2010-01-01	51.180000000000000
2011-01-01	49.542700000000000
2012-01-01	47.478500000000000
2013-01-01	46.922000000000000
2014-01-01	51.996600000000000
2015-01-01	55.996500000000000
2016-01-01	59.908600000000000