Year | Value | 2022 | 24.063 | 2021 | 23.781 | 2020 | 23.52 | 2019 | 23.279 | 2018 | 23.059 | 2017 | 22.858 | 2016 | 22.677 | 2015 | 22.515 | 2014 | 22.372 | 2013 | 22.248 | 2012 | 22.142 | 2011 | 22.054 | 2010 | 21.985 | 2009 | 21.934 | 2008 | 21.901 | 2007 | 21.868 | 2006 | 21.834 | 2005 | 21.801 | 2004 | 21.768 | 2003 | 21.735 | 2002 | 21.702 | 2001 | 21.67 | 2000 | 21.637 | 1999 | 21.604 | 1998 | 21.571 | 1997 | 21.538 | 1996 | 21.506 | 1995 | 21.473 | 1994 | 21.44 | 1993 | 21.408 | 1992 | 21.235 | 1991 | 21.023 | 1990 | 20.811 | 1989 | 20.602 | 1988 | 20.394 | 1987 | 20.187 | 1986 | 19.983 | 1985 | 19.779 | 1984 | 19.578 | 1983 | 19.377 | 1982 | 19.179 | 1981 | 18.982 | 1980 | 18.787 | 1979 | 18.592 | 1978 | 18.4 | 1977 | 17.413 | 1976 | 16.47 | 1975 | 15.566 | 1974 | 14.704 | 1973 | 13.882 | 1972 | 13.1 | 1971 | 12.313 | 1970 | 11.568 | 1969 | 10.862 | 1968 | 10.196 | 1967 | 9.564 | 1966 | 8.968 | 1965 | 8.406 | 1964 | 7.877 | 1963 | 7.527 | 1962 | 7.239 | 1961 | 6.962 | 1960 | 6.695 |
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