Year	Percent
1961-01-01	12.506100000000000
1962-01-01	11.551400000000000
1963-01-01	11.628100000000000
1964-01-01	9.742950000000000
1965-01-01	9.742950000000000
1966-01-01	9.742950000000000
1967-01-01	9.742950000000000
1968-01-01	16.880900000000000
1969-01-01	16.625000000000000
1970-01-01	10.818900000000000
1971-01-01	11.089700000000000
1972-01-01	11.434800000000000
1973-01-01	11.834800000000000
1974-01-01	12.649900000000000
1975-01-01	12.602200000000000
1976-01-01	12.445000000000000
1977-01-01	13.030700000000000
1978-01-01	13.458200000000000
1979-01-01	15.544900000000000
1980-01-01	19.098500000000000
1981-01-01	18.663600000000000
1982-01-01	18.230700000000000
1983-01-01	18.830300000000000
1984-01-01	17.980000000000000
1985-01-01	15.375800000000000
1986-01-01	15.055900000000000
1987-01-01	13.822800000000000
1988-01-01	12.017800000000000
1989-01-01	12.985400000000000
1990-01-01	13.726700000000000
1991-01-01	15.080900000000000
1992-01-01	16.788800000000000
1993-01-01	20.008500000000000
1994-01-01	19.776500000000000
1995-01-01	19.267800000000000
1996-01-01	18.513700000000000
1997-01-01	16.253200000000000
1998-01-01	11.395100000000000
1999-01-01	9.351389999999999
2000-01-01	9.626100000000000
2001-01-01	11.397900000000000
2002-01-01	13.170100000000000
2003-01-01	13.842400000000000
2004-01-01	13.806600000000000
2005-01-01	15.174000000000001
2006-01-01	16.208600000000000
2007-01-01	17.407400000000000
2008-01-01	17.081100000000000
2009-01-01	17.757300000000000
2010-01-01	18.637900000000000
2011-01-01	18.874800000000000
2012-01-01	18.778100000000000
2013-01-01	17.983900000000000
2014-01-01	18.108700000000000
2015-01-01	18.530000000000000
2016-01-01	17.601800000000000