Year	Percent
1960-01-01	1.945765183555640
1961-01-01	2.155172776709220
1962-01-01	4.263727121490850
1963-01-01	2.966958325308370
1964-01-01	3.444898482227660
1965-01-01	4.187224439980030
1966-01-01	4.174347618529970
1967-01-01	3.579952267303070
1968-01-01	3.888045654959060
1969-01-01	3.427461305534440
1970-01-01	5.515398542720560
1971-01-01	6.309606036111140
1972-01-01	6.458747944772440
1973-01-01	8.754676224468740
1974-01-01	15.275206221839400
1975-01-01	12.768198592051500
1976-01-01	10.249224652978400
1977-01-01	11.182021459570300
1978-01-01	8.618432862016370
1979-01-01	10.128892275368700
1980-01-01	13.555890411635000
1981-01-01	13.314405568007100
1982-01-01	10.768971899713900
1983-01-01	8.669271598085150
1984-01-01	7.067656383281740
1985-01-01	6.071390884281230
1986-01-01	4.235910110897930
1987-01-01	4.356108712217400
1988-01-01	5.085928613948810
1989-01-01	5.715991551356260
1990-01-01	6.456609061464050
1991-01-01	5.859585935395690
1992-01-01	4.156502638277460
1993-01-01	4.521823577916500
1994-01-01	2.877465423241590
1995-01-01	3.988880138885200
1996-01-01	2.773294407659490
1997-01-01	2.145706203232980
1998-01-01	1.957110949968190
1999-01-01	2.146313812361930
2000-01-01	2.972691419521270
2001-01-01	2.915184079418180
2002-01-01	2.444879901954290
2003-01-01	2.095235290722900
2004-01-01	2.216207889262730
2005-01-01	2.440596653547170
2006-01-01	2.495958512697480
2007-01-01	2.456354202620680
2008-01-01	4.070807158633000
2009-01-01	0.929319800043070
2010-01-01	1.800525775920390
2011-01-01	3.335090748635230
2012-01-01	2.470610590758390
2013-01-01	1.423422082378860
2014-01-01	0.592255588590948
2015-01-01	0.204336094071738
2016-01-01	0.439062364421389
2017-01-01	1.822643360590640