Year | Value | 2021 | 29.976 | 2020 | 30.309 | 2019 | 30.776 | 2018 | 31.158 | 2017 | 31.399 | 2016 | 31.659 | 2015 | 31.833 | 2014 | 32.085 | 2013 | 32.407 | 2012 | 32.818 | 2011 | 33.658 | 2010 | 34.836 | 2009 | 35.936 | 2008 | 36.979 | 2007 | 38.005 | 2006 | 38.825 | 2005 | 39.462 | 2004 | 39.889 | 2003 | 40.146 | 2002 | 40.388 | 2001 | 40.765 | 2000 | 40.923 | 1999 | 41.103 | 1998 | 41.208 | 1997 | 41.058 | 1996 | 41.05 | 1995 | 41.012 | 1994 | 41.452 | 1993 | 42.054 | 1992 | 42.442 | 1991 | 43.037 | 1990 | 44.25 | 1989 | 45.662 | 1988 | 46.844 | 1987 | 47.817 | 1986 | 48.591 | 1985 | 49.508 | 1984 | 50.643 | 1983 | 51.502 | 1982 | 52.063 | 1981 | 52.327 | 1980 | 52.182 | 1979 | 52.064 | 1978 | 51.569 | 1977 | 51.233 | 1976 | 50.936 | 1975 | 50.408 | 1974 | 50.126 | 1973 | 49.817 | 1972 | 49.427 | 1971 | 49.107 | 1970 | 48.797 | 1969 | 48.337 | 1968 | 47.841 | 1967 | 47.444 | 1966 | 47.276 | 1965 | 47.501 | 1964 | 48.039 | 1963 | 48.877 | 1962 | 49.845 | 1961 | 50.816 | 1960 | 51.657 |
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