Year	Percent
1980-01-01	5.323040000000000
1981-01-01	7.924210000000000
1982-01-01	8.876220000000000
1983-01-01	8.893950000000000
1984-01-01	8.387250000000000
1985-01-01	11.166100000000000
1986-01-01	11.489100000000000
1987-01-01	15.188200000000000
1988-01-01	17.938000000000000
1989-01-01	16.064800000000000
1990-01-01	16.965000000000000
1991-01-01	27.273500000000000
1992-01-01	23.685200000000000
1993-01-01	23.812600000000000
1994-01-01	25.462900000000000
1995-01-01	23.843100000000000
1996-01-01	21.343000000000004
1997-01-01	15.507400000000000
1998-01-01	10.799800000000000
1999-01-01	7.056000000000000
2000-01-01	6.672999999999999
2001-01-01	6.686420000000000
2002-01-01	5.657240000000000
2003-01-01	5.420840000000000
2004-01-01	5.570590000000000
2005-01-01	5.854300000000000
2006-01-01	6.043960000000000
2007-01-01	5.045370000000000
2008-01-01	5.693440000000000
2009-01-01	9.527030000000000
2010-01-01	18.804000000000002
2011-01-01	18.344000000000000
2012-01-01	23.021100000000000
2013-01-01	22.724000000000000
2014-01-01	22.924200000000000
2015-01-01	21.104600000000000
2016-01-01	20.686999999999998