Year	Percent
1975-01-01	7.880669999999999
1976-01-01	8.262200000000000
1977-01-01	8.205680000000001
1978-01-01	8.311000000000000
1979-01-01	9.481800000000000
1980-01-01	11.935300000000000
1981-01-01	12.989700000000000
1982-01-01	13.893100000000000
1983-01-01	17.898900000000000
1984-01-01	27.062400000000000
1985-01-01	29.651800000000000
1986-01-01	39.617800000000000
1987-01-01	52.114000000000000
1988-01-01	46.422200000000000
1989-01-01	38.209900000000000
1990-01-01	36.880400000000000
1991-01-01	33.865600000000000
1992-01-01	35.780300000000000
1993-01-01	43.459300000000000
1994-01-01	48.601500000000000
1995-01-01	57.770300000000000
1996-01-01	75.185100000000000
1997-01-01	94.500700000000000
1998-01-01	118.834000000000000
1999-01-01	161.112000000000000
2000-01-01	236.882999999999980
2001-01-01	241.173000000000000
2002-01-01	174.060999999999980
2003-01-01	144.894000000000000
2004-01-01	144.217000000000000
2005-01-01	172.597000000000000
2006-01-01	205.582000000000000
2007-01-01	254.615999999999990
2008-01-01	313.593000000000000
2009-01-01	285.378000000000000
2010-01-01	235.499000000000020
2011-01-01	250.950000000000000
2012-01-01	229.360000000000000
2013-01-01	197.874000000000020
2014-01-01	209.637000000000000
2015-01-01	223.025000000000000
2016-01-01	225.055999999999980
2017-01-01	212.147000000000020