Year | Value | 2021 | 17.545 | 2020 | 17.889 | 2019 | 18.337 | 2018 | 18.813 | 2017 | 19.298 | 2016 | 19.483 | 2015 | 20.307 | 2014 | 20.617 | 2013 | 21.141 | 2012 | 21.304 | 2011 | 21.507 | 2010 | 21.402 | 2009 | 21.411 | 2008 | 21.23 | 2007 | 21.271 | 2006 | 21.347 | 2005 | 21.398 | 2004 | 21.542 | 2003 | 21.749 | 2002 | 21.984 | 2001 | 22.249 | 2000 | 22.74 | 1999 | 23.176 | 1998 | 24.041 | 1997 | 24.649 | 1996 | 25.115 | 1995 | 25.655 | 1994 | 26.39 | 1993 | 27.209 | 1992 | 28.367 | 1991 | 29.092 | 1990 | 29.227 | 1989 | 29.823 | 1988 | 31.065 | 1987 | 32.446 | 1986 | 33.803 | 1985 | 34.891 | 1984 | 36.064 | 1983 | 37.363 | 1982 | 38.541 | 1981 | 39.086 | 1980 | 39.385 | 1979 | 39.642 | 1978 | 40.169 | 1977 | 40.869 | 1976 | 41.566 | 1975 | 42.262 | 1974 | 42.6 | 1973 | 43.259 | 1972 | 43.807 | 1971 | 44.151 | 1970 | 44.503 | 1969 | 44.8 | 1968 | 45.526 | 1967 | 46.352 | 1966 | 47.009 | 1965 | 47.585 | 1964 | 48.192 | 1963 | 48.847 | 1962 | 50.087 | 1961 | 50.317 | 1960 | 50.975 |
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