Year	Percent
1962-01-01	18.206500000000000
1963-01-01	17.363600000000000
1964-01-01	18.021500000000000
1965-01-01	19.789300000000000
1966-01-01	21.770100000000000
1967-01-01	22.706700000000000
1968-01-01	18.467500000000000
1969-01-01	17.683600000000000
1970-01-01	9.764289999999999
1971-01-01	9.268850000000000
1972-01-01	10.212700000000000
1973-01-01	8.238630000000000
1974-01-01	9.910060000000001
1975-01-01	12.535600000000000
1976-01-01	13.256800000000000
1977-01-01	12.209000000000001
1978-01-01	13.707500000000000
1979-01-01	13.796800000000000
1980-01-01	14.321400000000000
1981-01-01	14.134700000000000
1982-01-01	14.204400000000000
1983-01-01	14.763000000000000
1984-01-01	16.533200000000000
1985-01-01	19.118200000000000
1986-01-01	19.160300000000000
1987-01-01	18.422800000000000
1988-01-01	20.149700000000000
1989-01-01	18.614300000000000
1990-01-01	15.618500000000000
1991-01-01	15.792300000000000
1992-01-01	17.308000000000000
1993-01-01	17.449100000000000
1994-01-01	15.701700000000000
1995-01-01	15.234700000000000
1996-01-01	17.084600000000000
1997-01-01	18.024100000000000
1998-01-01	18.515200000000000
1999-01-01	17.215300000000000
2000-01-01	18.263100000000000
2001-01-01	17.756500000000000
2002-01-01	20.750400000000000
2003-01-01	26.038100000000000
2004-01-01	26.764900000000000
2005-01-01	25.101300000000000
2006-01-01	24.486900000000000
2007-01-01	24.197500000000000
2008-01-01	23.585300000000000
2009-01-01	22.583200000000000
2010-01-01	23.106300000000000
2011-01-01	22.594000000000000
2012-01-01	25.530200000000000
2013-01-01	26.878000000000000
2014-01-01	26.583400000000000
2015-01-01	27.235800000000000
2016-01-01	26.921000000000000