Year Percent 1971-01-01 0.062874000000000000 1972-01-01 0.550953999999999900 1973-01-01 0.136671000000000010 1974-01-01 0.152223000000000000 1975-01-01 0.340956000000000000 1976-01-01 0.529435000000000000 1977-01-01 0.470028000000000000 1978-01-01 0.226961000000000020 1979-01-01 0.069636000000000000 1980-01-01 0.108255999999999990 1981-01-01 0.319986000000000000 1982-01-01 0.412164000000000030 1983-01-01 1.362029999999999900 1984-01-01 1.164030000000000000 1985-01-01 -0.019150999999999998 1986-01-01 2.039080000000000000 1987-01-01 0.201071000000000000 1988-01-01 -0.431836999999999970 1989-01-01 0.721471000000000000 1990-01-01 -0.328397000000000000 1991-01-01 -1.481060000000000000 1992-01-01 -0.065396000000000010 1993-01-01 -0.113132000000000000 1994-01-01 -0.330425000000000000 1995-01-01 -0.152427000000000000 1996-01-01 0.168414000000000000 1997-01-01 -0.269106000000000000 1998-01-01 -0.601156999999999900 1999-01-01 -0.112943000000000000 2000-01-01 0.322248999999999950 2001-01-01 -0.162630000000000000 2002-01-01 -0.208805000000000020 2003-01-01 0.395696999999999970 2004-01-01 0.904632000000000000 2005-01-01 1.848240000000000000 2006-01-01 1.462079999999999800 2007-01-01 -0.283010000000000000 2008-01-01 1.975029999999999800 2009-01-01 0.056033000000000006 2010-01-01 -0.420814000000000000 2011-01-01 -2.052020000000000000 2012-01-01 1.650320000000000000 2013-01-01 0.142323000000000000 2014-01-01 0.605393000000000100 2015-01-01 -0.339199000000000000 2016-01-01 -0.877811000000000000