Year annual % 1961 -4.11875644872696 1962 3.8297230368173 1963 -5.5310798243809 1964 5.046294100286 1965 -8.6802152733344 1966 5.01204964505834 1967 -3.3353376221694 1968 -1.76021775860771 1969 7.47354810115466 1970 5.7554679780979 1971 -0.521678271511533 1972 1.26436212504169 1973 0.96633138955707 1974 -2.71812560617872 1975 2.63331346294339 1976 -3.97966345156419 1977 -1.35267825492055 1978 2.37939305579138 1979 4.18891806107833 1980 7.88469678258042 1981 2.06452272924145 1982 -10.2595022616057 1983 -12.9643464150947 1984 -1.69718077348399 1985 1.82649389645584 1986 10.2749918749492 1987 15.0851827538892 1988 -1.0173191123737 1989 0.104990476051213 1990 -4.25589707880459 1991 4.29856647073161 1992 13.5645968444087 1993 5.02097133690016 1994 8.08651602373622 1995 -4.365723494967 1996 7.50001106096394 1997 5.11968539818972 1998 4.88008764835132 1999 -0.906395948895849 2000 -2.84158712909979 2001 -4.23286000377195 2002 -9.52859863057276 2003 -3.93795064180256 2004 4.00192526282885 2005 5.87189307695388 2006 6.33752215135281 2007 6.88864975917667 2008 8.81863055117127 2009 2.00868479241795 2010 9.08910915896328 2011 6.84840165398855 2012 4.61778482590933 2013 5.20186619222116 2014 2.63367798722123 2015 -0.822991140024996 2016 -0.262395163639525 2017 4.2399445463987 2018 1.14378525294754