Year	Percent
1960-01-01	18.5924000000000000
1961-01-01	18.7460000000000000
1962-01-01	20.1990000000000000
1963-01-01	18.7018000000000000
1964-01-01	17.5591000000000000
1965-01-01	14.6006000000000000
1966-01-01	9.0912600000000000
1967-01-01	7.6558399999999995
1968-01-01	6.2940800000000000
1969-01-01	6.0983500000000000
1970-01-01	7.0383600000000010
1971-01-01	7.1676500000000000
1972-01-01	7.2535899999999990
1973-01-01	7.1468899999999990
1974-01-01	6.1660200000000000
1975-01-01	9.3928100000000000
1976-01-01	14.3393000000000000
1977-01-01	17.3023000000000000
1978-01-01	19.2725000000000000
1979-01-01	20.8556000000000000
1980-01-01	26.2855000000000000
1981-01-01	30.8633000000000000
1982-01-01	46.0153000000000000
1983-01-01	49.4337000000000000
1984-01-01	34.5339000000000000
1985-01-01	30.8882000000000000
1986-01-01	29.5467000000000000
1987-01-01	24.9230000000000020
1988-01-01	25.8126000000000000
1989-01-01	27.4270000000000000
1990-01-01	22.6081000000000000
1991-01-01	18.5243000000000000
1992-01-01	18.1602000000000000
1993-01-01	18.9535000000000000
1994-01-01	18.1015000000000000
1995-01-01	19.7768000000000000
1996-01-01	21.1725000000000000
1997-01-01	22.8260000000000000
1998-01-01	31.1099000000000000
1999-01-01	41.5100000000000000
2000-01-01	44.0052000000000000
2001-01-01	49.3010000000000000
2002-01-01	60.5027000000000000
2003-01-01	52.7549000000000000
2004-01-01	31.4991000000000000
2005-01-01	22.4154000000000000
2006-01-01	22.2223000000000000
2007-01-01	22.2497000000000000
2008-01-01	24.0432000000000000
2009-01-01	22.7868000000000000
2010-01-01	20.2500000000000000
2011-01-01	21.3642000000000000
2012-01-01	22.1384000000000000
2013-01-01	23.5985000000000000
2014-01-01	25.4326000000000000
2015-01-01	27.7778000000000000
2016-01-01	28.6552000000000000