Year	Percent
1980-01-01	68.038900000000000
1981-01-01	73.013400000000000
1982-01-01	12.665999999999999
1983-01-01	12.559000000000001
1984-01-01	12.725000000000000
1985-01-01	13.581000000000000
1986-01-01	13.682000000000000
1987-01-01	12.642999999999999
1988-01-01	74.818900000000000
1989-01-01	69.488200000000000
1990-01-01	64.356900000000000
1991-01-01	57.441700000000000
1992-01-01	61.442200000000000
1993-01-01	69.522600000000000
1994-01-01	14.173000000000000
1995-01-01	16.272000000000002
1996-01-01	19.447000000000000
1997-01-01	20.795000000000000
1998-01-01	20.795000000000000
1999-01-01	22.897000000000000
2000-01-01	18.612000000000002
2001-01-01	17.449300000000000
2002-01-01	17.508100000000000
2003-01-01	18.291300000000000
2004-01-01	17.260200000000000
2005-01-01	18.028700000000000
2006-01-01	16.640600000000000
2007-01-01	16.369300000000000
2008-01-01	16.204000000000000
2009-01-01	18.345600000000000
2010-01-01	18.357600000000000
2011-01-01	16.893100000000000
2012-01-01	18.662300000000000
2013-01-01	18.469300000000000
2014-01-01	18.967400000000000
2015-01-01	17.915300000000000
2016-01-01	16.958900000000000