Year	Percent
1960-01-01	4.098600000000000000
1961-01-01	5.209290000000000000
1962-01-01	6.315469999999999500
1963-01-01	5.724270000000000000
1964-01-01	3.669710000000000000
1965-01-01	2.375630000000000000
1966-01-01	1.871230000000000000
1967-01-01	1.838860000000000000
1968-01-01	3.231480000000000000
1969-01-01	3.898970000000000000
1970-01-01	4.136760000000000000
1971-01-01	3.526810000000000000
1972-01-01	2.636670000000000000
1973-01-01	2.418140000000000000
1974-01-01	3.347590000000000300
1975-01-01	5.668109999999999500
1976-01-01	5.080680000000000000
1977-01-01	4.202680000000000000
1978-01-01	4.185850000000000000
1979-01-01	3.969969999999999600
1980-01-01	2.926420000000000200
1981-01-01	2.191670000000000200
1982-01-01	1.591200000000000000
1983-01-01	1.982650000000000000
1984-01-01	2.693720000000000000
1985-01-01	3.132990000000000000
1986-01-01	2.618030000000000000
1987-01-01	2.268329999999999700
1988-01-01	3.418740000000000000
1989-01-01	3.649370000000000000
1990-01-01	2.410920000000000000
1991-01-01	2.113650000000000000
1992-01-01	2.299530000000000000
1993-01-01	2.461230000000000000
1994-01-01	4.325750000000000000
1995-01-01	4.850780000000000000
1996-01-01	3.093380000000000000
1997-01-01	2.248340000000000200
1998-01-01	1.518820000000000000
1999-01-01	0.716994999999999900
2000-01-01	0.622287000000000000
2001-01-01	0.459093999999999950
2002-01-01	0.264629000000000000
2003-01-01	0.160408000000000000
2004-01-01	0.052940000000000000
2005-01-01	0.013909999999999999
2006-01-01	0.030293000000000000
2007-01-01	0.175369000000000000
2008-01-01	8.184730000000000000
2009-01-01	13.707400000000000000
2010-01-01	10.347999999999999000
2011-01-01	10.637300000000000000
2012-01-01	10.624000000000000000
2013-01-01	9.639970000000000000
2014-01-01	8.251320000000000000
2015-01-01	5.664470000000000000
2016-01-01	2.851660000000000000