| Year | Value | | 2022 | 155.56248340585 | | 2021 | 146.99504425935 | | 2020 | 144.02915630904 | | 2019 | 143.17157812644 | | 2018 | 141.75327574752 | | 2017 | 140.32397877651 | | 2016 | 137.73404919935 | | 2015 | 133.6306949793 | | 2014 | 127.67928762034 | | 2013 | 120.81183760127 | | 2012 | 114.84034913916 | | 2011 | 105.10713289265 | | 2010 | 100 | | 2009 | 90.457461213963 | | 2008 | 84.556999977429 | | 2007 | 75.476872198151 | | 2006 | 69.9544001816 | | 2005 | 64.575515751922 | | 2004 | 60.421798322796 | | 2003 | 58.253852432949 | | 2002 | 56.115240980137 | | 2001 | 53.879221697498 | | 2000 | 51.052615400941 | | 1999 | 49.299803675143 | | 1998 | 47.660687845073 | | 1997 | 45.127795945812 | | 1996 | 43.548686282931 | | 1995 | 42.114854709035 | | 1994 | 40.039904612009 | | 1993 | 36.796413364452 | | 1992 | 33.199201552409 | | 1991 | 31.190574061224 | | 1990 | 30.05361510395 | | 1989 | 27.059623183128 | | 1988 | 24.283501305038 | | 1987 | 22.535116109309 | | 1986 | 20.347393095155 | | 1985 | 18.89376771118 | | 1984 | 17.555580580603 | | 1983 | 15.490020378224 | | 1982 | 13.449116890223 | | 1981 | 12.047427284877 | | 1980 | 10.537241746851 | | 1979 | 8.9701323338473 | | 1978 | 7.8190050841919 | | 1977 | 7.0916444594212 | | 1976 | 6.3462822673188 | | 1975 | 5.7332559213849 | | 1974 | 4.9010958872135 | | 1973 | 4.0164694120764 | | 1972 | 3.4983392845586 | | 1971 | 3.2006450829486 | | 1970 | 3.0914841362054 | | 1969 | 3.015378969107 | | 1968 | 2.943694051611 | | 1967 | 2.7197987999184 | | 1966 | 2.6629121093696 | | 1965 | 2.5581714122229 | | 1964 | 2.5133923618828 | | 1963 | 2.4918676681619 | | 1962 | 2.4015408284298 | | 1961 | 2.3319699433474 | | 1960 | 2.296992316035 |
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