Year | Value | 2022 | 38.012123896214 | 2021 | 37.515794324626 | 2020 | 37.029380852696 | 2019 | 36.550759347892 | 2018 | 36.078957795024 | 2017 | 35.612932485169 | 2016 | 35.150078753577 | 2015 | 34.687232354699 | 2014 | 34.233120747023 | 2013 | 33.792212051476 | 2012 | 33.359293140212 | 2011 | 32.932010398764 | 2010 | 32.487418652731 | 2009 | 32.045334925239 | 2008 | 31.6119109381 | 2007 | 31.17525525558 | 2006 | 30.853910972179 | 2005 | 30.474914614121 | 2004 | 30.102086283451 | 2003 | 29.751668647638 | 2002 | 29.407665824795 | 2001 | 29.067649028346 | 2000 | 28.717303632481 | 1999 | 28.40442618704 | 1998 | 28.103470646152 | 1997 | 27.802361478895 | 1996 | 27.515849173681 | 1995 | 27.256150826813 | 1994 | 26.91845333761 | 1993 | 26.550103526128 | 1992 | 26.19128736478 | 1991 | 25.821463841928 | 1990 | 25.440939268155 | 1989 | 25.006528884404 | 1988 | 24.558403534285 | 1987 | 24.074080617029 | 1986 | 23.57324498028 | 1985 | 23.059340499232 | 1984 | 22.545680179146 | 1983 | 22.073827566447 | 1982 | 21.649270450548 | 1981 | 21.261476247379 | 1980 | 20.851538026429 | 1979 | 20.426000515697 | 1978 | 20.021151047943 | 1977 | 19.554426028771 | 1976 | 19.104488502301 | 1975 | 18.654081284059 | 1974 | 18.211019112968 | 1973 | 17.776348039735 | 1972 | 17.32517913853 | 1971 | 16.87734262341 | 1970 | 16.438724248629 | 1969 | 16.007485316258 | 1968 | 15.559485637589 | 1967 | 15.126628534342 | 1966 | 14.705944657917 | 1965 | 14.298828176628 | 1964 | 13.887359024654 | 1963 | 13.489960205344 | 1962 | 13.115309581915 | 1961 | 12.758634945345 | 1960 | 12.411388121699 |
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