Year | Value | 2021 | 59.039291916233 | 2020 | 59.587233465602 | 2019 | 60.141485811524 | 2018 | 59.823171419324 | 2017 | 59.526188649743 | 2016 | 59.177157514543 | 2015 | 58.951610585538 | 2014 | 58.655286674778 | 2013 | 58.439477984549 | 2012 | 58.199426047075 | 2011 | 58.043817846444 | 2010 | 57.42680797023 | 2009 | 57.108014491122 | 2008 | 56.139179104042 | 2007 | 55.971853209271 | 2006 | 55.507696283048 | 2005 | 55.007477008646 | 2004 | 54.641183489814 | 2003 | 54.387834995171 | 2002 | 54.150561933881 | 2001 | 53.742015781022 | 2000 | 53.475434096433 | 1999 | 52.649612288128 | 1998 | 51.908242076212 | 1997 | 52.203384672761 | 1996 | 51.891778158984 | 1995 | 51.811926864267 | 1994 | 52.161408219471 | 1993 | 51.429711832488 | 1992 | 51.036543323879 | 1991 | 51.030508136163 | 1990 | 50.907085323849 | 1989 | 50.910849092743 | 1988 | 49.780002740787 | 1987 | 50.216792580482 | 1986 | 49.837126802858 | 1985 | 49.237882283461 | 1984 | 49.005189331152 | 1983 | 49.256265719422 | 1982 | 49.782275910271 | 1981 | 49.902472549183 | 1980 | 49.802721306629 | 1979 | 49.634845859689 | 1978 | 49.373725525977 | 1977 | 49.304327503966 | 1976 | 48.810739816499 | 1975 | 48.348657604683 | 1974 | 48.182876334373 | 1973 | 48.021517716316 | 1972 | 47.408867059606 | 1971 | 47.375095503032 | 1970 | 46.748735595171 | 1969 | 46.252213324691 | 1968 | 46.127941049588 | 1967 | 45.698306654274 | 1966 | 45.61778678298 | 1965 | 45.576871395058 | 1964 | 45.464344609583 | 1963 | 44.956369383665 | 1962 | 44.724120927492 | 1961 | 44.271384264788 | 1960 | 43.990553088542 |
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