Year | Value | 2022 | 28.343 | 2021 | 28.654 | 2020 | 28.961 | 2019 | 29.264 | 2018 | 29.562 | 2017 | 29.856 | 2016 | 30.145 | 2015 | 30.435 | 2014 | 30.728 | 2013 | 31.021 | 2012 | 31.316 | 2011 | 31.556 | 2010 | 31.673 | 2009 | 31.791 | 2008 | 31.908 | 2007 | 32.026 | 2006 | 32.144 | 2005 | 32.262 | 2004 | 32.38 | 2003 | 32.499 | 2002 | 32.618 | 2001 | 32.718 | 2000 | 32.778 | 1999 | 32.838 | 1998 | 32.898 | 1997 | 32.958 | 1996 | 33.018 | 1995 | 33.078 | 1994 | 33.138 | 1993 | 33.198 | 1992 | 33.258 | 1991 | 33.294 | 1990 | 33.274 | 1989 | 33.254 | 1988 | 33.234 | 1987 | 33.214 | 1986 | 33.194 | 1985 | 33.174 | 1984 | 33.154 | 1983 | 33.134 | 1982 | 33.114 | 1981 | 33.163 | 1980 | 33.36 | 1979 | 33.558 | 1978 | 33.757 | 1977 | 33.956 | 1976 | 34.156 | 1975 | 34.357 | 1974 | 34.558 | 1973 | 34.759 | 1972 | 34.961 | 1971 | 35.25 | 1970 | 35.728 | 1969 | 36.208 | 1968 | 36.691 | 1967 | 37.178 | 1966 | 37.666 | 1965 | 38.157 | 1964 | 38.65 | 1963 | 39.147 | 1962 | 39.645 | 1961 | 40.144 | 1960 | 40.639 |
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