Year Percent 1966-01-01 4.436860067690860 1967-01-01 -1.089324618742560 1968-01-01 6.057268722225240 1969-01-01 4.023883697331200 1970-01-01 -0.199650611430204 1971-01-01 3.850962740444590 1972-01-01 3.828557669173270 1973-01-01 6.006493506753080 1974-01-01 15.722307299093700 1975-01-01 15.709874598823300 1976-01-01 6.856551573645400 1977-01-01 6.834514041364860 1978-01-01 23.895620646930300 1979-01-01 36.540756998092600 1980-01-01 2.498519500301630 1981-01-01 12.167394348793800 1982-01-01 5.868096357226600 1983-01-01 8.151231356226330 1984-01-01 14.316869788325800 1985-01-01 3.804286836494260 1986-01-01 1.675675675675450 1987-01-01 7.113237639553400 1988-01-01 4.486797697041780 1989-01-01 11.661599847995800 1990-01-01 7.002169566511260 1991-01-01 8.996938734943250 1992-01-01 1.823333333333100 1993-01-01 9.679346580679280 1994-01-01 14.852814983397000 1995-01-01 19.263253638253800 1996-01-01 26.436781609195100 1997-01-01 31.111589831969400 1998-01-01 12.500410765337800 1999-01-01 3.385424273404550 2000-01-01 24.432024210215100 2001-01-01 9.296187713418850 2002-01-01 -1.365680053280610 2003-01-01 10.647464565830600 2004-01-01 8.176429374820590 2005-01-01 13.252069918822300 2006-01-01 2.745420002142460 2007-01-01 8.412062857725410 2008-01-01 24.406951035391400 2009-01-01 10.555435529952900 2010-01-01 6.493265914739960 2011-01-01 9.592166059796710 2012-01-01 18.161045306545100 2013-01-01 7.937958074924120 2014-01-01 4.405352341852900 2015-01-01 5.544688912597860 2016-01-01 5.557689614009650 2017-01-01 16.052535303039200