Year	Percent
1973-01-01	10.837300000000000
1974-01-01	10.126800000000000
1975-01-01	9.600880000000000
1976-01-01	9.161560000000000
1977-01-01	7.731170000000000
1978-01-01	7.503870000000000
1979-01-01	7.112089999999999
1980-01-01	8.673919999999999
1981-01-01	11.035400000000000
1982-01-01	12.107200000000000
1983-01-01	12.071400000000000
1984-01-01	14.306800000000000
1985-01-01	16.093900000000000
1986-01-01	17.740000000000000
1987-01-01	19.163500000000000
1988-01-01	15.842700000000000
1989-01-01	18.239700000000000
1990-01-01	19.306200000000000
1991-01-01	16.873500000000000
1992-01-01	14.492800000000000
1993-01-01	11.805400000000000
1994-01-01	10.215100000000000
1995-01-01	9.896590000000000
1996-01-01	8.895760000000001
1997-01-01	9.992430000000000
1998-01-01	12.322000000000001
1999-01-01	12.252300000000000
2000-01-01	11.252300000000000
2001-01-01	11.047100000000000
2002-01-01	9.789450000000000
2003-01-01	8.634950000000000
2004-01-01	8.462320000000000
2005-01-01	8.572339999999999
2006-01-01	10.061100000000000
2007-01-01	12.053400000000000
2008-01-01	15.239700000000000
2009-01-01	17.792500000000000
2010-01-01	16.615800000000000
2011-01-01	17.050600000000000
2012-01-01	17.981600000000000
2013-01-01	19.139000000000000
2014-01-01	17.923500000000000
2015-01-01	17.968700000000000
2016-01-01	17.439400000000000