Year	Percent
1973-01-01	8.504220000000000
1974-01-01	10.722200000000000
1975-01-01	11.309200000000000
1976-01-01	13.014500000000000
1977-01-01	20.551000000000000
1978-01-01	28.354500000000000
1979-01-01	22.459600000000000
1980-01-01	17.131100000000000
1981-01-01	16.505100000000000
1982-01-01	17.314200000000000
1983-01-01	18.453800000000000
1984-01-01	19.905000000000000
1985-01-01	22.487500000000000
1986-01-01	24.806500000000000
1987-01-01	35.682700000000000
1988-01-01	27.269700000000000
1989-01-01	23.051400000000000
1990-01-01	20.905300000000000
1991-01-01	21.110000000000000
1992-01-01	19.295700000000000
1993-01-01	16.901800000000000
1994-01-01	13.802000000000000
1995-01-01	13.490000000000000
1996-01-01	11.589600000000000
1997-01-01	12.241600000000000
1998-01-01	15.978200000000000
1999-01-01	14.565300000000000
2000-01-01	11.339000000000000
2001-01-01	12.456800000000000
2002-01-01	13.800800000000000
2003-01-01	13.699100000000000
2004-01-01	11.331500000000000
2005-01-01	9.340320000000000
2006-01-01	9.692410000000000
2007-01-01	12.033200000000000
2008-01-01	11.034600000000000
2009-01-01	11.056400000000000
2010-01-01	9.666319999999999
2011-01-01	10.385900000000000
2012-01-01	13.525800000000000
2013-01-01	17.023800000000000
2014-01-01	19.422200000000000
2015-01-01	20.500600000000000
2016-01-01	21.607500000000000