Year Percent 1960-01-01 1.536617039788710 1961-01-01 2.293697155662140 1962-01-01 2.843271924946660 1963-01-01 2.966958325308370 1964-01-01 2.335723499494950 1965-01-01 3.242322812806470 1966-01-01 3.533055523571950 1967-01-01 1.796052206140400 1968-01-01 1.470311644034260 1969-01-01 1.912666559285560 1970-01-01 3.450227843623720 1971-01-01 5.240979842300570 1972-01-01 5.484942487578440 1973-01-01 7.032018252629060 1974-01-01 6.986426985188830 1975-01-01 5.910339333745750 1976-01-01 4.246631855081830 1977-01-01 3.734168504708750 1978-01-01 2.718691505148060 1979-01-01 4.043621618809480 1980-01-01 5.441054605994030 1981-01-01 6.344245378500530 1982-01-01 5.241043941380720 1983-01-01 3.293412780538670 1984-01-01 2.405795378966500 1985-01-01 2.066239021517340 1986-01-01 -0.129416442513556 1987-01-01 0.249910957391677 1988-01-01 1.274117481212200 1989-01-01 2.780562482116480 1990-01-01 2.696469975508480 1991-01-01 4.047031827448530 1992-01-01 5.056980056980050 1993-01-01 4.474576271186450 1994-01-01 2.693056456846200 1995-01-01 1.706161137440770 1996-01-01 1.449725587656620 1997-01-01 1.939369194651410 1998-01-01 0.911184539901888 1999-01-01 0.585433617781321 2000-01-01 1.440268323961710 2001-01-01 1.983856851113480 2002-01-01 1.420806713073350 2003-01-01 1.034223392252700 2004-01-01 1.665736087846650 2005-01-01 1.546910755148730 2006-01-01 1.577429241031220 2007-01-01 2.298340580353150 2008-01-01 2.628383067314360 2009-01-01 0.312737722931282 2010-01-01 1.103808560835860 2011-01-01 2.075172931077590 2012-01-01 2.008491182233830 2013-01-01 1.504722266688010 2014-01-01 0.906797035167963 2015-01-01 0.234429944518262 2016-01-01 0.483355422156377 2017-01-01 1.737916052447820