Year | Value | 2021 | 31.36 | 2020 | 31.914 | 2019 | 32.549 | 2018 | 33.099 | 2017 | 33.568 | 2016 | 34.011 | 2015 | 34.558 | 2014 | 35.533 | 2013 | 36.473 | 2012 | 37.569 | 2011 | 38.282 | 2010 | 38.887 | 2009 | 39.658 | 2008 | 40.324 | 2007 | 40.796 | 2006 | 41.429 | 2005 | 41.71 | 2004 | 42.271 | 2003 | 43.486 | 2002 | 44.345 | 2001 | 44.706 | 2000 | 44.991 | 1999 | 45.185 | 1998 | 45.386 | 1997 | 45.511 | 1996 | 45.756 | 1995 | 45.683 | 1994 | 45.971 | 1993 | 46.029 | 1992 | 45.923 | 1991 | 45.828 | 1990 | 45.812 | 1989 | 45.876 | 1988 | 46.154 | 1987 | 46.412 | 1986 | 46.446 | 1985 | 46.43 | 1984 | 46.506 | 1983 | 46.466 | 1982 | 46.463 | 1981 | 46.448 | 1980 | 46.537 | 1979 | 46.739 | 1978 | 46.981 | 1977 | 47.002 | 1976 | 47.123 | 1975 | 47.326 | 1974 | 47.512 | 1973 | 47.381 | 1972 | 47.536 | 1971 | 47.675 | 1970 | 47.814 | 1969 | 48.032 | 1968 | 48.284 | 1967 | 48.612 | 1966 | 48.68 | 1965 | 48.836 | 1964 | 49.096 | 1963 | 49.11 | 1962 | 49.004 | 1961 | 49.021 | 1960 | 48.891 |
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