Year	Percent
1973-01-01	9.3416500000000000
1974-01-01	10.3536000000000000
1975-01-01	12.0985000000000000
1976-01-01	13.1482000000000000
1977-01-01	12.2886000000000000
1978-01-01	14.3229000000000000
1979-01-01	21.3784000000000000
1980-01-01	22.8697000000000000
1981-01-01	13.7583000000000000
1982-01-01	10.6290000000000010
1983-01-01	10.6290000000000010
1984-01-01	10.7055000000000000
1985-01-01	13.2474000000000000
1986-01-01	16.6372000000000000
1987-01-01	18.2920000000000000
1988-01-01	15.8324000000000000
1989-01-01	12.6709000000000000
1990-01-01	10.4690000000000010
1991-01-01	10.9288000000000000
1992-01-01	11.0323000000000000
1993-01-01	8.5960700000000000
1994-01-01	5.6813800000000000
1995-01-01	5.0713900000000000
1996-01-01	5.1124600000000000
1997-01-01	5.1423900000000000
1998-01-01	4.9049900000000000
1999-01-01	4.8719800000000010
2000-01-01	4.7090500000000000
2001-01-01	4.7156199999999995
2002-01-01	5.2027900000000000
2003-01-01	5.5662900000000000
2004-01-01	4.2823100000000000
2005-01-01	3.9602600000000000
2006-01-01	4.4976199999999995
2007-01-01	3.6868600000000000
2008-01-01	3.7505500000000000
2009-01-01	5.1581600000000000
2010-01-01	5.1533600000000000
2011-01-01	5.2930400000000000
2012-01-01	6.1203000000000000
2013-01-01	6.9380700000000000
2014-01-01	8.0691800000000010
2015-01-01	11.2071000000000000