Year Percent 1960-01-01 0.332829047091756 1961-01-01 0.693606754935318 1962-01-01 -3.003076587907820 1963-01-01 0.746645708135420 1964-01-01 3.660982948854650 1965-01-01 14.839004461624100 1966-01-01 9.036440658176320 1967-01-01 0.701897484353739 1968-01-01 -1.675759424569110 1969-01-01 3.409820282437420 1970-01-01 3.762898595805360 1971-01-01 3.140421713941980 1972-01-01 2.102363346101120 1973-01-01 5.112184039087570 1974-01-01 10.024317751648400 1975-01-01 9.669695481512440 1976-01-01 10.317415887741300 1977-01-01 12.732162792989100 1978-01-01 11.078100382614000 1979-01-01 9.904360512311260 1980-01-01 20.819224932421900 1981-01-01 10.317284224539500 1982-01-01 14.823008849557700 1983-01-01 16.079873883342000 1984-01-01 17.036366379960800 1985-01-01 12.106756059824700 1986-01-01 23.864289821736600 1987-01-01 19.693593314763000 1988-01-01 17.663486153130000 1989-01-01 21.261867088607800 1990-01-01 16.756374707769100 1991-01-01 19.748544819557800 1992-01-01 13.637424171721800 1993-01-01 12.089792286897700 1994-01-01 8.154231285871010 1995-01-01 15.742230502159600 1996-01-01 7.187103697199910 1997-01-01 4.625605788264400 1998-01-01 3.872575464274920 1999-01-01 3.079499126383280 2000-01-01 2.683805353485480 2001-01-01 2.269757204759530 2002-01-01 2.737238550003340 2003-01-01 4.507776363193070 2004-01-01 11.270619332052000 2005-01-01 4.869396968719870 2006-01-01 7.644526445264300 2007-01-01 9.318969057992330 2008-01-01 18.316831683168400 2009-01-01 11.763495438644400 2010-01-01 11.265188265318600 2011-01-01 10.053916904535400 2012-01-01 7.118155619596540 2013-01-01 9.421576540220590 2014-01-01 10.144571203776600 2015-01-01 10.362069735256000 2016-01-01 13.809668284789700 2017-01-01 29.501932732038900