Year	Percent
1973-01-01	12.300100000000000
1974-01-01	11.442500000000000
1975-01-01	13.416300000000000
1976-01-01	13.803100000000000
1977-01-01	14.177100000000000
1978-01-01	15.036700000000000
1979-01-01	14.552100000000000
1980-01-01	12.165999999999999
1981-01-01	14.789600000000000
1982-01-01	15.970000000000000
1983-01-01	20.043900000000000
1984-01-01	18.575800000000000
1985-01-01	16.388900000000000
1986-01-01	19.166500000000000
1987-01-01	17.290400000000000
1988-01-01	15.267700000000000
1989-01-01	11.351800000000000
1990-01-01	11.101400000000000
1991-01-01	11.238600000000000
1992-01-01	11.644800000000000
1993-01-01	13.551100000000000
1994-01-01	18.178500000000000
1995-01-01	22.598300000000000
1996-01-01	24.109800000000000
1997-01-01	24.795000000000000
1998-01-01	27.089400000000000
1999-01-01	33.499300000000000
2000-01-01	33.247300000000000
2001-01-01	24.608100000000000
2002-01-01	21.616400000000000
2003-01-01	17.951500000000000
2004-01-01	17.709100000000000
2005-01-01	19.034500000000000
2006-01-01	20.059400000000000
2007-01-01	20.980700000000000
2008-01-01	20.930100000000000
2009-01-01	22.596999999999998
2010-01-01	22.493500000000000
2011-01-01	23.815000000000000
2012-01-01	25.346000000000000
2013-01-01	26.365700000000000
2014-01-01	27.174100000000000
2015-01-01	28.745000000000000
2016-01-01	29.911200000000000