Year | Value | 2022 | 35.824998649514 | 2021 | 35.351924992679 | 2020 | 34.89320578862 | 2019 | 34.444634057876 | 2018 | 34.005899197975 | 2017 | 33.578613442355 | 2016 | 33.162340635483 | 2015 | 32.755806006546 | 2014 | 32.35853413733 | 2013 | 31.970276045619 | 2012 | 31.590545925138 | 2011 | 31.219043068445 | 2010 | 30.855392700646 | 2009 | 30.493168568932 | 2008 | 30.133976109624 | 2007 | 29.774648357502 | 2006 | 29.418567427559 | 2005 | 29.068671235821 | 2004 | 28.721078548889 | 2003 | 28.376391612937 | 2002 | 28.039666133254 | 2001 | 27.702820863047 | 2000 | 27.424189877317 | 1999 | 27.185145023142 | 1998 | 26.951286029553 | 1997 | 26.714403450998 | 1996 | 26.476766669177 | 1995 | 26.240197451945 | 1994 | 26.008955840965 | 1993 | 25.781157569343 | 1992 | 25.559336210947 | 1991 | 25.336239523302 | 1990 | 25.079064674231 | 1989 | 24.810629890659 | 1988 | 24.543485800454 | 1987 | 24.271533061546 | 1986 | 24.001877272246 | 1985 | 23.735447901525 | 1984 | 23.476012474648 | 1983 | 23.220235485087 | 1982 | 22.963249142747 | 1981 | 22.699941531182 | 1980 | 22.304321358027 | 1979 | 21.85960337483 | 1978 | 21.434400826026 | 1977 | 21.02269846856 | 1976 | 20.620740139076 | 1975 | 20.228190438169 | 1974 | 19.84726970541 | 1973 | 19.500692264557 | 1972 | 19.175246174503 | 1971 | 18.846156769423 | 1970 | 18.595867250246 | 1969 | 18.385424330104 | 1968 | 18.181923642994 | 1967 | 17.982277001133 | 1966 | 17.785364733699 | 1965 | 17.5908734339 | 1964 | 17.398917323536 | 1963 | 17.207628226987 | 1962 | 17.018853104611 | 1961 | 16.831982920403 | 1960 | 16.69883477928 |
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