Year annual % 1961 2.3514851485148514 1962 12.333736396614269 1963 34.33799784714747 1964 -7.732371794871796 1965 -8.076422058184976 1966 7.8885214926783185 1967 3.1085814360770576 1968 0.8492569002123143 1969 0.9263157894736843 1970 4.476428869420109 1971 4.624046639779579 1972 19.270256860425174 1973 20.6016 1974 22.213967310549776 1975 18.664785062961357 1976 10.489049892968879 1977 4.321907600596125 1978 15.682539682539682 1979 16.67124039517014 1980 16.982241561801718 1981 20.418216547702826 1982 13.165803973952245 1983 15.603098487642935 1984 17.65156349712827 1985 -1.773703623345628 1986 31.3380087249434 1987 -24.6552304069963 1988 29.927455357142858 1989 32.21663874930207 1990 37.65592515592516 1991 36.89116481026996 1992 34.187660535434155 1993 26.967204395837047 1994 33.201011732584966 1995 38.93476746430441 1996 39.04871357198234 1997 28.07760694488024 1998 33.66595002061521 1999 29.538655528772445 2000 42.440323475750844 2001 43.64109828445956 2002 35.58647715081485 2003 0.7332813076221502 2004 32.09073881848937 2005 27.30854749668686 2006 27.31114361789429 2007 29.9210073504003 2008 14.892204193397394 2009 30.63739217879979 2010 42.499726815695354 2011 30.60134017945636 2012 32.559016931347244 2013 31.4251476008941 2014 20.956889978489023 2015 30.672917389954335 2016 17.448873725492195 2017 20.54242234797438 2018 14.570314266996338 2019 15.544426082997312 2020 18.17737711572925