Year Percent 1960-01-01 2.228112420670830 1961-01-01 6.789823404402430 1962-01-01 9.408194068265560 1963-01-01 6.581137364640580 1964-01-01 5.172750423288170 1965-01-01 7.708333264204980 1966-01-01 7.930367544484480 1967-01-01 1.706093160059380 1968-01-01 2.079221858136220 1969-01-01 2.458054256177990 1970-01-01 6.110742035987380 1971-01-01 11.972570922966300 1972-01-01 12.881467716976100 1973-01-01 20.032367164509700 1974-01-01 39.679977097286000 1975-01-01 39.306734224561200 1976-01-01 31.310865267313500 1977-01-01 34.616716871162500 1978-01-01 50.550938232593200 1979-01-01 78.310024532916700 1980-01-01 131.024998340780000 1981-01-01 116.800011462711000 1982-01-01 120.364381812063000 1983-01-01 145.951515575109000 1984-01-01 373.215652132421000 1985-01-01 304.584147213124000 1986-01-01 48.133342845602500 1987-01-01 19.852613484433700 1988-01-01 16.258329323326900 1989-01-01 20.249449383237900 1990-01-01 17.173344373784700 1991-01-01 19.005946336284700 1992-01-01 11.948019765766200 1993-01-01 10.943942218746200 1994-01-01 12.350000912015000 1995-01-01 10.043018816847600 1996-01-01 11.276626074070400 1997-01-01 9.001151357101090 1998-01-01 5.434842778198670 1999-01-01 5.200000293362160 2000-01-01 1.124838234124540 2001-01-01 1.099999254792720 2002-01-01 5.687440026806580 2003-01-01 0.716666277155599 2004-01-01 -0.413701746023948 2005-01-01 1.329347357561190 2006-01-01 2.107249088822520 2007-01-01 0.491664700233525 2008-01-01 4.594076805883860 2009-01-01 3.325001415412020 2010-01-01 2.693766947864550 2011-01-01 3.458334985077660 2012-01-01 1.707614720498860 2013-01-01 1.549995739034650 2014-01-01 0.475954281452880 2015-01-01 -0.600006527400082 2016-01-01 -0.544937550051134 2017-01-01 0.242241245108701