Year	Percent
1960-01-01	85.464800000000000
1961-01-01	79.104100000000000
1962-01-01	75.453000000000000
1963-01-01	61.622500000000000
1964-01-01	65.517300000000000
1965-01-01	60.008300000000000
1966-01-01	56.683500000000000
1967-01-01	59.915900000000000
1968-01-01	60.758200000000000
1969-01-01	67.361200000000000
1970-01-01	78.173100000000000
1971-01-01	64.330800000000000
1972-01-01	58.047900000000000
1973-01-01	71.301900000000000
1974-01-01	86.423200000000000
1975-01-01	107.962000000000000
1976-01-01	115.146000000000000
1977-01-01	102.340000000000000
1978-01-01	105.482999999999990
1979-01-01	100.761000000000010
1980-01-01	58.478000000000000
1981-01-01	89.021300000000000
1982-01-01	71.601000000000000
1983-01-01	99.968800000000000
1984-01-01	91.562000000000010
1985-01-01	66.923000000000000
1986-01-01	67.824200000000000
1987-01-01	69.757400000000000
1988-01-01	79.099400000000000
1989-01-01	87.383800000000000
1990-01-01	85.616000000000000
1991-01-01	80.448900000000000
1992-01-01	73.738000000000000
1993-01-01	79.028900000000000
1994-01-01	68.912700000000000
1995-01-01	67.178700000000000
1996-01-01	55.000600000000000
1997-01-01	60.823200000000000
1998-01-01	55.860800000000000
1999-01-01	62.673400000000000
2000-01-01	61.412900000000000
2001-01-01	61.100600000000000
2002-01-01	60.943000000000005
2003-01-01	57.167000000000000
2004-01-01	50.174800000000000
2005-01-01	42.915200000000000
2006-01-01	36.533900000000000
2007-01-01	29.531200000000000
2008-01-01	24.698600000000000
2009-01-01	23.855300000000000
2010-01-01	23.980700000000000
2011-01-01	22.750700000000000
2012-01-01	22.269700000000000
2013-01-01	24.275000000000000
2014-01-01	24.275000000000000
2015-01-01	28.854600000000000
2016-01-01	24.458800000000000