Year annual % 1961 18.089758342922906 1962 13.973884233092951 1963 19.97264021887826 1964 21.55074116305586 1965 16.67448405253284 1966 25.949748743718597 1967 7.125758059368013 1968 12.66294227188082 1969 10.221487603305778 1970 14.76216183792215 1971 18.058749738657735 1972 25.92641785097624 1973 32.749709946208206 1974 44.31378780655754 1975 23.22811525050468 1976 47.47494303542973 1977 29.411764705882355 1978 12.999609832227854 1979 14.849905737903029 1980 39.0390408446724 1981 27.217176959003638 1982 230.41740176832315 1983 172.7497191392699 1984 1428.9156444726082 1985 6987.876844130854 1986 184.37173686042465 1987 94.94492044063647 1988 27.839517799962326 1989 21.433131967977996 1990 52.865520728008086 1991 50.73288178643243 1992 34.473679591371045 1993 33.7027319836577 1994 24.21142037078619 1995 7.6577249255291555 1996 39.83793949713084 1997 18.964518025868607 1998 13.423188236240419 1999 3.2305785239107925 2000 1.5531229511930456 2001 26.021966468823177 2002 -5.801499814062018 2003 14.22090746464547 2004 -5.108574449839134 2005 13.845423805528648 2006 23.359095118394293 2007 26.94017770089871 2008 24.691554788902938 2009 10.128223510549034 2010 12.633709892338482 2011 22.96629093600348 2012 19.368503685142343 2013 18.108705229731594 2014 15.643839512598792 2015 13.140045089471055 2016 0.002490991771996164 2017 9.990157420602467 2018 4.13051568387533 2019 -1.5614816070535282 2020 9.279325006904013 2021 6.358249516239957