Year	Percent
1980-01-01	28.165700000000000
1981-01-01	22.655300000000000
1982-01-01	18.382900000000000
1983-01-01	14.838600000000000
1984-01-01	15.617300000000000
1985-01-01	15.071000000000000
1986-01-01	14.455800000000000
1987-01-01	15.483700000000000
1988-01-01	16.171300000000000
1989-01-01	17.835400000000000
1990-01-01	19.270800000000000
1991-01-01	19.500100000000000
1992-01-01	21.282600000000000
1993-01-01	15.597200000000000
1994-01-01	21.017600000000000
1995-01-01	21.730700000000000
1996-01-01	19.990800000000000
1997-01-01	15.575900000000000
1998-01-01	14.129200000000000
1999-01-01	13.456000000000000
2000-01-01	16.646300000000000
2001-01-01	14.378400000000000
2002-01-01	13.691700000000000
2003-01-01	13.323100000000000
2004-01-01	12.271500000000000
2005-01-01	14.063400000000000
2006-01-01	12.327300000000000
2007-01-01	9.167750000000000
2008-01-01	8.664450000000000
2009-01-01	7.922590000000000
2010-01-01	7.865710000000001
2011-01-01	9.484810000000001
2012-01-01	10.101700000000000
2013-01-01	9.504210000000000
2014-01-01	10.601100000000000
2015-01-01	12.586700000000000
2016-01-01	13.055000000000000
2017-01-01	11.986700000000000