Year | Value | 2021 | 58.781 | 2020 | 58.812 | 2019 | 59.984 | 2018 | 59.556 | 2017 | 59.046 | 2016 | 58.813 | 2015 | 58.343 | 2014 | 57.896 | 2013 | 57.585 | 2012 | 57.194 | 2011 | 56.746 | 2010 | 56.261 | 2009 | 55.84 | 2008 | 55.455 | 2007 | 54.95 | 2006 | 54.479 | 2005 | 53.919 | 2004 | 53.502 | 2003 | 53.04 | 2002 | 52.509 | 2001 | 52.072 | 2000 | 51.596 | 1999 | 51.156 | 1998 | 50.864 | 1997 | 50.489 | 1996 | 50.157 | 1995 | 50.03 | 1994 | 49.889 | 1993 | 49.76 | 1992 | 49.545 | 1991 | 49.438 | 1990 | 49.318 | 1989 | 49.047 | 1988 | 48.905 | 1987 | 48.735 | 1986 | 48.45 | 1985 | 48.108 | 1984 | 47.718 | 1983 | 47.442 | 1982 | 47.025 | 1981 | 46.548 | 1980 | 45.992 | 1979 | 38.408 | 1978 | 38.633 | 1977 | 38.358 | 1976 | 26.279 | 1975 | 33.379 | 1974 | 38.114 | 1973 | 41.753 | 1972 | 41.599 | 1971 | 33.935 | 1970 | 27.701 | 1969 | 27.532 | 1968 | 42.163 | 1967 | 41.97 | 1966 | 41.706 | 1965 | 41.517 | 1964 | 41.218 | 1963 | 41.027 | 1962 | 40.741 | 1961 | 40.441 | 1960 | 40.2 |
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