Year annual % 1961 8.484005563282336 1962 9.401709401709402 1963 0.234375 1964 10.093530787217459 1965 4.530973451327434 1966 4.470030477480528 1967 2.2366288492706645 1968 23.747622067216234 1969 17.371252882398156 1970 -5.588299497926217 1971 11.07514450867052 1972 17.631140716069943 1973 26.11927092549991 1974 18.633366072681355 1975 8.33826138379657 1976 22.194323144104803 1977 21.701063164477798 1978 31.61797092937895 1979 19.65530704445312 1980 21.56341770381765 1981 2.622799953985966 1982 56.798565183275414 1983 31.629491945477074 1984 28.31073374730706 1985 71.09700176366843 1986 88.40061023378551 1987 64.01796344281813 1988 56.876297628642035 1989 74.1981798077741 1990 73.99875393545464 1991 76.21328900335561 1992 33.238357588456914 1993 21.922502300787645 1994 8.808349075423811 1995 19.6147186069182 1996 29.6479534577533 1997 47.13861384620054 1998 11.265844282987624 1999 37.7996807093934 2000 12.075808523188854 2001 31.218959315151245 2002 29.088607565939633 2003 22.022590320554855 2004 20.15133194962388 2005 31.14542540092526 2006 21.660547821925856 2007 17.10933172217011 2008 26.538996313804187 2009 34.52962528887426 2010 24.15489336582022 2011 29.62799220540015 2012 21.984690436063886 2013 10.676316045456533 2014 23.915452909160162 2015 -99.88824335381811 2016 17.861897706294712 2017 6.990975136338813 2018 14.451124041743324 2019 14.309255200269414 2020 38.179941059849334 2021 22.05201918577734 2022 41.74420871191486 2023 32.83245635931501