Year | Value | 2022 | 33.693 | 2021 | 33.781 | 2020 | 33.851 | 2019 | 33.905 | 2018 | 33.94 | 2017 | 33.959 | 2016 | 33.96 | 2015 | 33.944 | 2014 | 33.911 | 2013 | 33.86 | 2012 | 33.792 | 2011 | 33.724 | 2010 | 33.656 | 2009 | 33.588 | 2008 | 33.521 | 2007 | 33.453 | 2006 | 33.385 | 2005 | 33.318 | 2004 | 33.263 | 2003 | 33.336 | 2002 | 33.409 | 2001 | 33.483 | 2000 | 33.556 | 1999 | 33.629 | 1998 | 33.703 | 1997 | 33.777 | 1996 | 33.85 | 1995 | 33.924 | 1994 | 33.998 | 1993 | 34.072 | 1992 | 34.146 | 1991 | 34.22 | 1990 | 34.294 | 1989 | 34.368 | 1988 | 34.443 | 1987 | 34.517 | 1986 | 34.592 | 1985 | 34.666 | 1984 | 34.741 | 1983 | 34.816 | 1982 | 34.89 | 1981 | 34.965 | 1980 | 35.04 | 1979 | 37.197 | 1978 | 39.403 | 1977 | 41.654 | 1976 | 43.936 | 1975 | 46.251 | 1974 | 48.579 | 1973 | 50.913 | 1972 | 53.24 | 1971 | 54.284 | 1970 | 54.052 | 1969 | 53.82 | 1968 | 53.588 | 1967 | 53.356 | 1966 | 53.123 | 1965 | 52.891 | 1964 | 52.659 | 1963 | 52.628 | 1962 | 52.665 | 1961 | 52.703 | 1960 | 52.74 |
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