Year	Percent
1975-01-01	81.37350000000000
1976-01-01	93.46170000000000
1977-01-01	85.42880000000000
1978-01-01	66.56870000000000
1979-01-01	73.22770000000000
1980-01-01	60.99110000000000
1981-01-01	66.92310000000000
1982-01-01	232.21700000000000
1983-01-01	228.44500000000000
1984-01-01	230.06599999999997
1985-01-01	216.32800000000000
1986-01-01	193.40099999999998
1987-01-01	235.92400000000000
1988-01-01	184.84400000000002
1989-01-01	177.59599999999998
1990-01-01	167.43200000000002
1991-01-01	145.15000000000000
1992-01-01	134.93300000000000
1993-01-01	124.11200000000001
1994-01-01	128.97799999999998
1995-01-01	108.40299999999999
1996-01-01	98.38850000000000
1997-01-01	87.55980000000000
1998-01-01	67.98410000000000
1999-01-01	57.50480000000000
2000-01-01	53.82620000000000
2001-01-01	48.59570000000000
2002-01-01	50.10170000000000
2003-01-01	48.09550000000000
2004-01-01	41.49950000000000
2005-01-01	35.62590000000000
2006-01-01	34.10160000000000
2007-01-01	35.04760000000000
2008-01-01	30.78260000000000
2009-01-01	29.36420000000000
2010-01-01	25.57160000000000
2011-01-01	23.29020000000000
2012-01-01	20.70410000000000
2013-01-01	18.32600000000000
2014-01-01	15.03090000000000
2015-01-01	14.79830000000000
2016-01-01	14.99810000000000
2017-01-01	15.19140000000000