Year	Percent
1980-01-01	8.3986100000000010
1981-01-01	7.2841300000000000
1982-01-01	5.5799100000000000
1983-01-01	7.2407200000000000
1984-01-01	15.1644000000000000
1985-01-01	18.2859999999999980
1986-01-01	23.8106000000000000
1987-01-01	27.7748000000000000
1988-01-01	24.7185000000000000
1989-01-01	20.0556000000000000
1990-01-01	18.4390000000000000
1991-01-01	17.1592000000000000
1992-01-01	16.2798000000000000
1993-01-01	16.8367000000000000
1994-01-01	16.0259000000000000
1995-01-01	15.0215000000000000
1996-01-01	14.4934000000000000
1997-01-01	19.9887000000000000
1998-01-01	22.5977000000000000
1999-01-01	23.0136000000000000
2000-01-01	17.9360000000000000
2001-01-01	24.2042000000000000
2002-01-01	13.3748000000000000
2003-01-01	12.7567000000000000
2004-01-01	5.4860300000000000
2005-01-01	3.6311199999999997
2006-01-01	3.7264000000000000
2007-01-01	3.4178200000000000
2008-01-01	2.5464800000000000
2009-01-01	4.5362700000000000
2010-01-01	4.1661700000000000
2011-01-01	9.9030800000000010
2012-01-01	4.5192200000000000
2013-01-01	6.7432200000000000
2014-01-01	15.6227000000000000
2015-01-01	24.0829000000000000
2016-01-01	20.6212000000000000