Year	Percent
1975-01-01	0.5103320000000000
1976-01-01	0.6280470000000000
1977-01-01	0.6280470000000000
1978-01-01	0.6774950000000000
1979-01-01	0.7171180000000000
1980-01-01	0.6587550000000000
1981-01-01	0.4622720000000000
1982-01-01	0.5345350000000000
1983-01-01	1.2065100000000000
1984-01-01	1.6837200000000000
1985-01-01	1.6991100000000000
1986-01-01	2.4925000000000000
1987-01-01	3.5611500000000000
1988-01-01	5.8823099999999995
1989-01-01	9.0369200000000000
1990-01-01	12.2408000000000000
1991-01-01	21.7826000000000000
1992-01-01	32.9128000000000000
1993-01-01	33.8469000000000000
1994-01-01	30.1597000000000000
1995-01-01	23.2671000000000000
1996-01-01	22.5353000000000000
1997-01-01	25.9458000000000000
1998-01-01	22.1373000000000000
1999-01-01	20.1387000000000000
2000-01-01	20.0396000000000000
2001-01-01	16.7458000000000000
2002-01-01	14.6996000000000000
2003-01-01	14.7202000000000000
2004-01-01	18.3539000000000000
2005-01-01	23.6154000000000000
2006-01-01	29.9004000000000000
2007-01-01	35.2479000000000000
2008-01-01	28.2836000000000000
2009-01-01	30.0954000000000000
2010-01-01	39.2401000000000000
2011-01-01	36.7191000000000000
2012-01-01	37.7439000000000000
2013-01-01	41.8375000000000000
2014-01-01	37.4650000000000000
2015-01-01	34.2381000000000000
2016-01-01	32.0007000000000000
2017-01-01	33.2519999999999950