Year	Percent
1960-01-01	27.900000000000000
1961-01-01	27.900000000000000
1962-01-01	29.350000000000000
1963-01-01	18.000000000000000
1964-01-01	16.616700000000000
1965-01-01	16.687500000000000
1966-01-01	17.500000000000000
1967-01-01	21.208300000000000
1968-01-01	25.300000000000000
1969-01-01	27.768700000000000
1970-01-01	20.927400000000000
1971-01-01	15.513900000000000
1972-01-01	14.840600000000000
1973-01-01	16.596300000000000
1974-01-01	19.764200000000000
1975-01-01	13.701200000000000
1976-01-01	11.169100000000000
1977-01-01	15.201500000000000
1978-01-01	17.564900000000000
1979-01-01	18.426300000000000
1980-01-01	19.633800000000000
1981-01-01	19.199000000000000
1982-01-01	14.360100000000000
1983-01-01	11.971800000000000
1984-01-01	11.664900000000000
1985-01-01	9.636080000000000
1986-01-01	13.504300000000000
1987-01-01	14.293900000000000
1988-01-01	14.002500000000000
1989-01-01	9.739800000000000
1990-01-01	5.759430000000000
1991-01-01	6.924189999999999
1992-01-01	10.276300000000000
1993-01-01	15.043000000000000
1994-01-01	17.875200000000000
1995-01-01	18.957600000000000
1996-01-01	19.370900000000000
1997-01-01	22.032600000000000
1998-01-01	25.260700000000000
1999-01-01	28.505400000000000
2000-01-01	29.218600000000000
2001-01-01	28.090300000000000
2002-01-01	23.734700000000000
2003-01-01	24.612500000000000
2004-01-01	25.844000000000000
2005-01-01	26.150200000000000
2006-01-01	25.719400000000000
2007-01-01	25.169000000000000
2008-01-01	22.650700000000000
2009-01-01	23.524800000000000
2010-01-01	22.215300000000000
2011-01-01	21.862200000000000
2012-01-01	23.647600000000000
2013-01-01	24.287800000000000
2014-01-01	22.841400000000000
2015-01-01	24.169600000000000
2016-01-01	24.726400000000000