Year	Percent
1978-01-01	4.6037200000000000
1979-01-01	3.3895199999999996
1980-01-01	2.5016700000000003
1981-01-01	2.1023800000000000
1982-01-01	1.7075300000000000
1983-01-01	1.7130900000000002
1984-01-01	3.2357500000000000
1985-01-01	5.4501700000000000
1986-01-01	9.7195800000000000
1987-01-01	14.6318000000000000
1988-01-01	16.7673000000000000
1989-01-01	14.7581000000000000
1990-01-01	9.5303899999999990
1991-01-01	8.9300800000000000
1992-01-01	6.5446599999999995
1993-01-01	8.8018200000000000
1994-01-01	6.1246700000000000
1995-01-01	5.6856400000000000
1996-01-01	7.3964300000000005
1997-01-01	5.6642400000000000
1998-01-01	7.1975800000000000
1999-01-01	9.7518200000000000
2000-01-01	9.6267800000000000
2001-01-01	10.5837000000000000
2002-01-01	10.4238000000000000
2003-01-01	8.3499500000000000
2004-01-01	7.1384100000000000
2005-01-01	5.8940300000000000
2006-01-01	6.5272800000000000
2007-01-01	9.7078400000000000
2008-01-01	7.4775100000000005
2009-01-01	13.8721000000000000
2010-01-01	12.0047000000000000
2011-01-01	10.4588000000000000
2012-01-01	10.3525000000000000
2013-01-01	11.7264000000000000
2014-01-01	11.2699000000000000
2015-01-01	12.5216000000000000
2016-01-01	20.7813000000000000