Year | Value | 2022 | 37.731 | 2021 | 37.44 | 2020 | 37.165 | 2019 | 36.907 | 2018 | 36.666 | 2017 | 36.442 | 2016 | 36.234 | 2015 | 36.026 | 2014 | 35.819 | 2013 | 35.613 | 2012 | 35.408 | 2011 | 35.202 | 2010 | 34.997 | 2009 | 34.793 | 2008 | 34.59 | 2007 | 34.387 | 2006 | 34.184 | 2005 | 33.982 | 2004 | 33.781 | 2003 | 33.58 | 2002 | 33.38 | 2001 | 33.18 | 2000 | 32.982 | 1999 | 32.783 | 1998 | 32.585 | 1997 | 32.348 | 1996 | 32.092 | 1995 | 31.836 | 1994 | 31.582 | 1993 | 31.329 | 1992 | 31.077 | 1991 | 30.826 | 1990 | 30.576 | 1989 | 30.327 | 1988 | 30.08 | 1987 | 29.833 | 1986 | 29.588 | 1985 | 29.344 | 1984 | 29.101 | 1983 | 28.859 | 1982 | 28.619 | 1981 | 28.38 | 1980 | 28.066 | 1979 | 27.715 | 1978 | 27.368 | 1977 | 27.023 | 1976 | 26.681 | 1975 | 26.341 | 1974 | 26.005 | 1973 | 25.671 | 1972 | 25.353 | 1971 | 25.084 | 1970 | 24.817 | 1969 | 24.552 | 1968 | 24.289 | 1967 | 24.028 | 1966 | 23.769 | 1965 | 23.511 | 1964 | 23.256 | 1963 | 23.002 | 1962 | 22.751 | 1961 | 22.501 | 1960 | 22.104 |
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