Year | Value | 2021 | 21.413 | 2020 | 22.405 | 2019 | 23.292 | 2018 | 23.836 | 2017 | 24.222 | 2016 | 25.365 | 2015 | 26.352 | 2014 | 26.677 | 2013 | 26.333 | 2012 | 25.297 | 2011 | 24.13 | 2010 | 23.349 | 2009 | 23.613 | 2008 | 22.753 | 2007 | 21.352 | 2006 | 19.841 | 2005 | 18.673 | 2004 | 18.477 | 2003 | 18.675 | 2002 | 19.378 | 2001 | 19.935 | 2000 | 20.419 | 1999 | 20.769 | 1998 | 21.097 | 1997 | 21.847 | 1996 | 22.992 | 1995 | 24.216 | 1994 | 25.329 | 1993 | 26.833 | 1992 | 29.281 | 1991 | 31.901 | 1990 | 33.841 | 1989 | 34.987 | 1988 | 36.376 | 1987 | 37.139 | 1986 | 37.623 | 1985 | 38.348 | 1984 | 38.525 | 1983 | 38.482 | 1982 | 38.424 | 1981 | 38.293 | 1980 | 38.324 | 1979 | 38.583 | 1978 | 38.909 | 1977 | 39.036 | 1976 | 39.209 | 1975 | 39.613 | 1974 | 39.967 | 1973 | 40.168 | 1972 | 40.298 | 1971 | 40.472 | 1970 | 40.785 | 1969 | 41.172 | 1968 | 41.88 | 1967 | 42.613 | 1966 | 43.452 | 1965 | 43.891 | 1964 | 44.497 | 1963 | 44.849 | 1962 | 45.136 | 1961 | 44.839 | 1960 | 44.788 |
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