Year | Value | 2021 | 30.537 | 2020 | 31.009 | 2019 | 31.518 | 2018 | 32.074 | 2017 | 32.516 | 2016 | 33.171 | 2015 | 33.96 | 2014 | 35.122 | 2013 | 36.246 | 2012 | 36.804 | 2011 | 37.205 | 2010 | 37.056 | 2009 | 36.749 | 2008 | 35.59 | 2007 | 34.81 | 2006 | 34.501 | 2005 | 34.947 | 2004 | 35.45 | 2003 | 35.88 | 2002 | 35.924 | 2001 | 35.961 | 2000 | 35.637 | 1999 | 35.263 | 1998 | 34.521 | 1997 | 33.799 | 1996 | 33.19 | 1995 | 32.625 | 1994 | 32.818 | 1993 | 33.142 | 1992 | 34.125 | 1991 | 34.412 | 1990 | 34.796 | 1989 | 35.578 | 1988 | 37.211 | 1987 | 39.157 | 1986 | 40.505 | 1985 | 41.976 | 1984 | 43.413 | 1983 | 45.119 | 1982 | 45.918 | 1981 | 46.494 | 1980 | 46.218 | 1979 | 46.321 | 1978 | 46.613 | 1977 | 46.725 | 1976 | 47.121 | 1975 | 47.265 | 1974 | 47.215 | 1973 | 47.002 | 1972 | 46.522 | 1971 | 46.194 | 1970 | 46.065 | 1969 | 45.973 | 1968 | 45.949 | 1967 | 45.949 | 1966 | 46.058 | 1965 | 46.246 | 1964 | 46.398 | 1963 | 46.611 | 1962 | 46.867 | 1961 | 47.039 | 1960 | 47.26 |
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