Year	Percent
1960-01-01	12.671000000000000
1961-01-01	11.924100000000000
1962-01-01	12.397800000000000
1963-01-01	13.560900000000000
1964-01-01	13.862000000000000
1965-01-01	15.373200000000000
1966-01-01	16.781100000000000
1967-01-01	16.445800000000000
1968-01-01	14.822600000000000
1969-01-01	13.416400000000000
1970-01-01	17.348200000000000
1971-01-01	14.932700000000000
1972-01-01	13.938900000000000
1973-01-01	14.034200000000000
1974-01-01	13.740400000000000
1975-01-01	13.807200000000000
1976-01-01	14.919100000000000
1977-01-01	14.510800000000000
1978-01-01	14.870100000000000
1979-01-01	18.799300000000000
1980-01-01	18.850300000000000
1981-01-01	21.512700000000000
1982-01-01	24.215000000000000
1983-01-01	32.825700000000000
1984-01-01	42.457200000000000
1985-01-01	35.741400000000000
1986-01-01	29.039800000000000
1987-01-01	26.893300000000000
1988-01-01	25.606500000000000
1989-01-01	8.829800000000000
1990-01-01	8.730960000000001
1991-01-01	4.900350000000000
1992-01-01	8.193210000000000
1993-01-01	8.388800000000000
1994-01-01	11.160800000000000
1995-01-01	13.629900000000000
1996-01-01	16.967300000000000
1997-01-01	22.676600000000000
1998-01-01	30.612100000000000
1999-01-01	28.409500000000000
2000-01-01	29.002100000000000
2001-01-01	26.772100000000000
2002-01-01	26.489600000000000
2003-01-01	27.715400000000000
2004-01-01	27.716800000000000
2005-01-01	27.206600000000000
2006-01-01	26.041300000000000
2007-01-01	24.948400000000000
2008-01-01	24.369800000000000
2009-01-01	25.703300000000000
2010-01-01	27.305700000000000
2011-01-01	26.859100000000000
2012-01-01	27.025800000000000
2013-01-01	29.441100000000000
2014-01-01	30.486000000000000
2015-01-01	31.708800000000000
2016-01-01	33.666100000000000