Year | Value | 2021 | 20.627 | 2020 | 20.946 | 2019 | 21.281 | 2018 | 21.664 | 2017 | 21.962 | 2016 | 22.263 | 2015 | 22.428 | 2014 | 22.402 | 2013 | 22.249 | 2012 | 22.069 | 2011 | 22.324 | 2010 | 22.606 | 2009 | 22.921 | 2008 | 23.191 | 2007 | 23.45 | 2006 | 23.742 | 2005 | 24.047 | 2004 | 24.443 | 2003 | 24.932 | 2002 | 25.591 | 2001 | 26.342 | 2000 | 27.171 | 1999 | 27.947 | 1998 | 28.734 | 1997 | 29.524 | 1996 | 30.272 | 1995 | 31.002 | 1994 | 31.713 | 1993 | 32.364 | 1992 | 33.032 | 1991 | 33.691 | 1990 | 34.264 | 1989 | 34.752 | 1988 | 35.337 | 1987 | 35.719 | 1986 | 36.062 | 1985 | 36.452 | 1984 | 36.589 | 1983 | 36.636 | 1982 | 36.566 | 1981 | 36.531 | 1980 | 35.903 | 1979 | 35.401 | 1978 | 34.932 | 1977 | 34.941 | 1976 | 34.811 | 1975 | 34.898 | 1974 | 35.024 | 1973 | 35.214 | 1972 | 35.493 | 1971 | 35.995 | 1970 | 36.68 | 1969 | 37.316 | 1968 | 38.037 | 1967 | 38.845 | 1966 | 39.705 | 1965 | 40.481 | 1964 | 41.052 | 1963 | 41.481 | 1962 | 41.585 | 1961 | 41.722 | 1960 | 41.849 |
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