Year	Percent
1975-01-01	4.8168700000000000
1976-01-01	4.3995300000000000
1977-01-01	3.2046799999999998
1978-01-01	2.0059800000000000
1979-01-01	3.2325600000000000
1980-01-01	2.6676200000000000
1981-01-01	2.6676200000000000
1982-01-01	2.6676200000000000
1983-01-01	2.6676200000000000
1984-01-01	2.6676200000000000
1985-01-01	2.6676200000000000
1986-01-01	36.6619000000000000
1987-01-01	59.0617000000000000
1988-01-01	58.4245000000000000
1989-01-01	42.3166000000000000
1990-01-01	45.3769999999999950
1991-01-01	41.6084000000000000
1992-01-01	55.9523000000000000
1993-01-01	87.1585000000000000
1994-01-01	95.3540000000000000
1995-01-01	77.5630000000000000
1996-01-01	81.6686000000000000
1997-01-01	173.0950000000000000
1998-01-01	197.1750000000000000
1999-01-01	131.2110000000000000
2000-01-01	174.3910000000000000
2001-01-01	181.0690000000000200
2002-01-01	125.6160000000000000
2003-01-01	139.4390000000000000
2004-01-01	199.4580000000000000
2005-01-01	226.9350000000000000
2006-01-01	303.4370000000000000
2007-01-01	642.5910000000000000
2008-01-01	822.3170000000000000
2009-01-01	692.4710000000000000
2010-01-01	628.6440000000000000
2011-01-01	589.4209999999999000
2012-01-01	478.7000000000000000
2013-01-01	423.8520000000000000
2014-01-01	464.4030000000000000
2015-01-01	562.9240000000000000
2016-01-01	532.0680000000000000
2017-01-01	481.5340000000000000