Year	Percent
1975-01-01	65.727700000000000
1976-01-01	39.751600000000000
1977-01-01	37.768400000000000
1978-01-01	36.724000000000004
1979-01-01	29.949800000000000
1980-01-01	26.572900000000000
1981-01-01	29.319300000000000
1982-01-01	30.318400000000000
1983-01-01	32.319400000000000
1984-01-01	32.368200000000000
1985-01-01	31.090700000000000
1986-01-01	30.542700000000000
1987-01-01	33.850300000000000
1988-01-01	35.777400000000000
1989-01-01	37.184700000000000
1990-01-01	39.164800000000000
1991-01-01	40.386300000000000
1992-01-01	42.822300000000000
1993-01-01	42.644400000000000
1994-01-01	38.930500000000000
1995-01-01	42.366000000000010
1996-01-01	45.503400000000000
1997-01-01	55.886200000000000
1998-01-01	54.150300000000000
1999-01-01	55.431200000000000
2000-01-01	55.726000000000006
2001-01-01	61.591300000000000
2002-01-01	64.208800000000000
2003-01-01	64.149000000000000
2004-01-01	60.578500000000000
2005-01-01	57.317500000000000
2006-01-01	58.906800000000000
2007-01-01	59.949300000000000
2008-01-01	65.179000000000000
2009-01-01	74.048700000000000
2010-01-01	78.981500000000000
2011-01-01	77.947800000000000
2012-01-01	71.118400000000000
2013-01-01	69.444500000000000
2014-01-01	61.844900000000000
2015-01-01	53.789200000000000
2016-01-01	47.622500000000000