Year	Percent
1980-01-01	6.1000000000000000
1981-01-01	5.5183300000000010
1982-01-01	5.7300000000000000
1983-01-01	3.3691699999999996
1984-01-01	2.6758300000000000
1985-01-01	5.3408300000000000
1986-01-01	8.5816699999999990
1987-01-01	9.8050000000000000
1988-01-01	9.3908300000000010
1989-01-01	9.2675000000000000
1990-01-01	6.6258300000000006
1991-01-01	6.8425000000000000
1992-01-01	11.1875000000000000
1993-01-01	16.1200000000000000
1994-01-01	13.0467000000000000
1995-01-01	20.3700000000000000
1996-01-01	14.6667000000000000
1997-01-01	18.9958000000000000
1998-01-01	15.1850000000000000
1999-01-01	12.8883000000000000
2000-01-01	8.6853100000000010
2001-01-01	7.2898600000000010
2002-01-01	6.9928300000000005
2003-01-01	7.0924100000000010
2004-01-01	7.3864300000000010
2005-01-01	7.5455500000000000
2006-01-01	8.3860700000000000
2007-01-01	8.3108300000000010
2008-01-01	7.7024300000000006
2009-01-01	6.7584500000000000
2010-01-01	14.0124000000000000
2011-01-01	15.2302000000000000
2012-01-01	13.8773000000000000
2013-01-01	14.0208000000000000
2014-01-01	12.6945000000000000
2015-01-01	13.0818000000000000
2016-01-01	12.9327000000000000