Year	Percent
1968-01-01	0.020
1969-01-01	0.210
1970-01-01	0.210
1971-01-01	0.120
1972-01-01	0.155
1973-01-01	0.020
1974-01-01	0.240
1975-01-01	0.060
1976-01-01	0.120
1977-01-01	0.190
1978-01-01	0.015
1979-01-01	0.080
1980-01-01	0.085
1981-01-01	0.135
1982-01-01	0.135
1983-01-01	0.250
1984-01-01	0.315
1985-01-01	0.140
1986-01-01	0.120
1987-01-01	-0.025
1988-01-01	0.160
1989-01-01	0.170
1990-01-01	0.145
1991-01-01	0.290
1992-01-01	0.375
1993-01-01	0.430
1994-01-01	0.430
1995-01-01	0.490
1996-01-01	0.900
1997-01-01	0.315
1998-01-01	-0.025
1999-01-01	0.975
2000-01-01	0.220
2001-01-01	1.770
2002-01-01	0.590
2003-01-01	1.625
2004-01-01	1.255
2005-01-01	1.330
2006-01-01	2.585
2007-01-01	0.430
2008-01-01	1.865
2009-01-01	0.660
2010-01-01	-0.470
2011-01-01	0.260
2012-01-01	0.450
2013-01-01	0.105
2014-01-01	-0.070
2015-01-01	-0.450