Year	Percent
1974-01-01	0.8938719999999999
1975-01-01	2.5199200000000000
1976-01-01	4.0014199999999995
1977-01-01	6.2120300000000000
1978-01-01	10.4369000000000000
1979-01-01	15.1586000000000000
1980-01-01	20.5138000000000000
1981-01-01	25.5777000000000000
1982-01-01	26.1608000000000000
1983-01-01	26.6059000000000000
1984-01-01	29.0665000000000000
1985-01-01	30.5227000000000000
1986-01-01	31.1262000000000000
1987-01-01	28.2615000000000000
1988-01-01	27.5460000000000000
1989-01-01	25.9899000000000000
1990-01-01	24.3101000000000000
1991-01-01	22.3318000000000000
1992-01-01	19.8627000000000000
1993-01-01	17.1291000000000000
1994-01-01	13.3962000000000000
1995-01-01	9.5174200000000000
1996-01-01	8.0696000000000000
1997-01-01	7.0510000000000000
1998-01-01	7.2488700000000000
1999-01-01	7.5852699999999995
2000-01-01	7.5856400000000000
2001-01-01	7.5441300000000000
2002-01-01	8.6467300000000000
2003-01-01	7.1206500000000000
2004-01-01	5.3930000000000000
2005-01-01	3.8874699999999995
2006-01-01	3.3632500000000000
2007-01-01	2.8813500000000000
2008-01-01	2.3603000000000000
2009-01-01	2.3519900000000002
2010-01-01	2.3707500000000000
2011-01-01	2.3847200000000000
2012-01-01	2.3633700000000000
2013-01-01	2.2823300000000000
2014-01-01	2.8888599999999998
2015-01-01	3.8771900000000000
2016-01-01	4.1352000000000000