Year | Value | 2022 | 18.491 | 2021 | 18.758 | 2020 | 19.025 | 2019 | 19.291 | 2018 | 19.556 | 2017 | 19.82 | 2016 | 20.083 | 2015 | 20.345 | 2014 | 20.606 | 2013 | 20.865 | 2012 | 21.122 | 2011 | 21.378 | 2010 | 21.631 | 2009 | 21.883 | 2008 | 22.132 | 2007 | 22.379 | 2006 | 22.623 | 2005 | 22.87 | 2004 | 23.117 | 2003 | 23.368 | 2002 | 23.62 | 2001 | 23.873 | 2000 | 24.129 | 1999 | 24.386 | 1998 | 24.583 | 1997 | 24.75 | 1996 | 24.918 | 1995 | 25.088 | 1994 | 25.257 | 1993 | 25.428 | 1992 | 25.599 | 1991 | 25.771 | 1990 | 25.944 | 1989 | 26.05 | 1988 | 26.125 | 1987 | 26.2 | 1986 | 26.275 | 1985 | 26.35 | 1984 | 26.425 | 1983 | 26.5 | 1982 | 26.575 | 1981 | 26.648 | 1980 | 26.718 | 1979 | 26.789 | 1978 | 26.86 | 1977 | 26.932 | 1976 | 27.003 | 1975 | 27.074 | 1974 | 27.35 | 1973 | 27.744 | 1972 | 28.14 | 1971 | 28.541 | 1970 | 28.945 | 1969 | 29.352 | 1968 | 29.762 | 1967 | 30.643 | 1966 | 31.775 | 1965 | 32.929 | 1964 | 34.102 | 1963 | 35.298 | 1962 | 36.511 | 1961 | 37.393 | 1960 | 38.12 |
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