Year | Value | 2022 | 35.872 | 2021 | 35.393 | 2020 | 34.926 | 2019 | 34.472 | 2018 | 34.03 | 2017 | 33.6 | 2016 | 33.182 | 2015 | 32.777 | 2014 | 32.384 | 2013 | 32.003 | 2012 | 31.634 | 2011 | 31.276 | 2010 | 30.93 | 2009 | 30.587 | 2008 | 30.246 | 2007 | 29.906 | 2006 | 29.569 | 2005 | 29.235 | 2004 | 28.903 | 2003 | 28.572 | 2002 | 28.244 | 2001 | 27.918 | 2000 | 27.667 | 1999 | 27.453 | 1998 | 27.24 | 1997 | 27.028 | 1996 | 26.817 | 1995 | 26.607 | 1994 | 26.399 | 1993 | 26.191 | 1992 | 25.984 | 1991 | 25.778 | 1990 | 25.547 | 1989 | 25.305 | 1988 | 25.063 | 1987 | 24.823 | 1986 | 24.585 | 1985 | 24.348 | 1984 | 24.113 | 1983 | 23.879 | 1982 | 23.647 | 1981 | 23.417 | 1980 | 23.098 | 1979 | 22.736 | 1978 | 22.379 | 1977 | 22.026 | 1976 | 21.677 | 1975 | 21.332 | 1974 | 20.991 | 1973 | 20.653 | 1972 | 20.321 | 1971 | 19.991 | 1970 | 19.76 | 1969 | 19.562 | 1968 | 19.366 | 1967 | 19.171 | 1966 | 18.977 | 1965 | 18.785 | 1964 | 18.595 | 1963 | 18.405 | 1962 | 18.218 | 1961 | 18.032 | 1960 | 17.924 |
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