Year | Value | 2021 | 29.107 | 2020 | 29.166 | 2019 | 29.058 | 2018 | 30.147 | 2017 | 32.651 | 2016 | 35.15 | 2015 | 36.325 | 2014 | 38.48 | 2013 | 39.27 | 2012 | 39.872 | 2011 | 40.255 | 2010 | 40.18 | 2009 | 40.508 | 2008 | 40.691 | 2007 | 40.798 | 2006 | 41.565 | 2005 | 43.519 | 2004 | 45.496 | 2003 | 47.464 | 2002 | 49.484 | 2001 | 50.594 | 2000 | 51.432 | 1999 | 52.306 | 1998 | 52.842 | 1997 | 53.423 | 1996 | 53.897 | 1995 | 54.045 | 1994 | 54.453 | 1993 | 54.767 | 1992 | 55.056 | 1991 | 55.269 | 1990 | 55.467 | 1989 | 55.78 | 1988 | 55.346 | 1987 | 54.116 | 1986 | 54.292 | 1985 | 53.885 | 1984 | 52.199 | 1983 | 50.618 | 1982 | 48.595 | 1981 | 48.927 | 1980 | 49.326 | 1979 | 49.763 | 1978 | 50.202 | 1977 | 50.619 | 1976 | 51.004 | 1975 | 51.355 | 1974 | 51.682 | 1973 | 52.003 | 1972 | 52.254 | 1971 | 52.422 | 1970 | 52.467 | 1969 | 52.345 | 1968 | 52.186 | 1967 | 51.968 | 1966 | 51.651 | 1965 | 51.329 | 1964 | 51.104 | 1963 | 50.822 | 1962 | 50.489 | 1961 | 50.23 | 1960 | 49.956 |
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