Year	Percent
1971-01-01	6.87013999999999900
1972-01-01	6.03853000000000100
1973-01-01	5.64896999999999900
1974-01-01	4.96629000000000000
1975-01-01	4.59955999999999900
1976-01-01	6.10395000000000000
1977-01-01	5.79139000000000000
1978-01-01	3.33475999999999970
1979-01-01	2.86959000000000000
1980-01-01	2.80179000000000000
1981-01-01	2.26682000000000000
1982-01-01	3.18398000000000000
1983-01-01	3.66964000000000020
1984-01-01	3.34658000000000030
1985-01-01	3.10809000000000020
1986-01-01	3.19163000000000000
1987-01-01	2.62792000000000000
1988-01-01	2.55927999999999980
1989-01-01	3.30485999999999970
1990-01-01	2.28534000000000000
1991-01-01	1.52790000000000000
1992-01-01	1.00897000000000010
1993-01-01	0.93956700000000000
1994-01-01	0.78528199999999990
1995-01-01	0.44158700000000000
1996-01-01	0.36752300000000000
1997-01-01	0.24590200000000000
1998-01-01	0.33380100000000000
1999-01-01	0.48785400000000000
2000-01-01	0.40632300000000000
2001-01-01	0.29848800000000003
2002-01-01	0.45207700000000006
2003-01-01	0.47272800000000000
2004-01-01	5.25625000000000000
2005-01-01	3.47489000000000030
2006-01-01	3.08882999999999970
2007-01-01	2.91004000000000000
2008-01-01	2.94625000000000000
2009-01-01	3.04510999999999980
2010-01-01	2.62694000000000030
2011-01-01	2.38730000000000000
2012-01-01	2.17361000000000000
2013-01-01	2.42368000000000000
2014-01-01	2.24950000000000000
2015-01-01	2.13325000000000000
2016-01-01	1.99514000000000010
2017-01-01	1.87896000000000000