Year | Value | 2022 | 42.779 | 2021 | 42.583 | 2020 | 42.398 | 2019 | 42.225 | 2018 | 42.064 | 2017 | 41.914 | 2016 | 41.777 | 2015 | 41.638 | 2014 | 41.501 | 2013 | 41.363 | 2012 | 41.225 | 2011 | 41.088 | 2010 | 40.926 | 2009 | 40.731 | 2008 | 40.536 | 2007 | 40.341 | 2006 | 40.147 | 2005 | 39.781 | 2004 | 39.247 | 2003 | 38.714 | 2002 | 38.022 | 2001 | 37.175 | 2000 | 36.337 | 1999 | 35.86 | 1998 | 35.654 | 1997 | 35.354 | 1996 | 34.822 | 1995 | 34.071 | 1994 | 33.33 | 1993 | 32.596 | 1992 | 31.872 | 1991 | 31.154 | 1990 | 30.594 | 1989 | 30.432 | 1988 | 30.515 | 1987 | 30.598 | 1986 | 30.682 | 1985 | 30.766 | 1984 | 30.849 | 1983 | 30.933 | 1982 | 31.017 | 1981 | 31.101 | 1980 | 31.186 | 1979 | 31.27 | 1978 | 31.355 | 1977 | 31.307 | 1976 | 30.815 | 1975 | 30.326 | 1974 | 29.842 | 1973 | 29.362 | 1972 | 28.888 | 1971 | 28.417 | 1970 | 27.951 | 1969 | 27.524 | 1968 | 27.122 | 1967 | 26.723 | 1966 | 26.328 | 1965 | 25.553 | 1964 | 24.669 | 1963 | 23.805 | 1962 | 22.962 | 1961 | 22.141 | 1960 | 21.383 |
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