Year | Value | 2021 | 36.21 | 2020 | 36.651 | 2019 | 37.113 | 2018 | 37.525 | 2017 | 38.058 | 2016 | 38.379 | 2015 | 38.741 | 2014 | 38.893 | 2013 | 38.721 | 2012 | 38.329 | 2011 | 39.076 | 2010 | 39.729 | 2009 | 40.183 | 2008 | 40.668 | 2007 | 41.143 | 2006 | 41.747 | 2005 | 42.069 | 2004 | 41.96 | 2003 | 41.838 | 2002 | 41.871 | 2001 | 42.12 | 2000 | 42.131 | 1999 | 42.223 | 1998 | 42.389 | 1997 | 42.537 | 1996 | 42.504 | 1995 | 42.453 | 1994 | 42.476 | 1993 | 42.755 | 1992 | 43.083 | 1991 | 43.476 | 1990 | 43.782 | 1989 | 44.213 | 1988 | 44.583 | 1987 | 44.965 | 1986 | 45.402 | 1985 | 46.051 | 1984 | 46.496 | 1983 | 47.192 | 1982 | 47.425 | 1981 | 47.698 | 1980 | 48.108 | 1979 | 48.585 | 1978 | 49.09 | 1977 | 49.337 | 1976 | 49.496 | 1975 | 49.818 | 1974 | 49.926 | 1973 | 49.8 | 1972 | 49.783 | 1971 | 49.825 | 1970 | 49.653 | 1969 | 49.506 | 1968 | 49.357 | 1967 | 49.351 | 1966 | 49.506 | 1965 | 49.546 | 1964 | 49.627 | 1963 | 49.654 | 1962 | 49.594 | 1961 | 49.569 | 1960 | 49.375 |
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