Year | Value | 2022 | 37.668 | 2021 | 37.264 | 2020 | 36.875 | 2019 | 36.5 | 2018 | 36.14 | 2017 | 35.793 | 2016 | 35.46 | 2015 | 35.141 | 2014 | 34.836 | 2013 | 34.545 | 2012 | 34.255 | 2011 | 33.966 | 2010 | 33.678 | 2009 | 33.391 | 2008 | 33.106 | 2007 | 32.822 | 2006 | 32.539 | 2005 | 32.257 | 2004 | 31.977 | 2003 | 31.698 | 2002 | 31.42 | 2001 | 31.144 | 2000 | 30.869 | 1999 | 30.595 | 1998 | 30.323 | 1997 | 30.052 | 1996 | 29.77 | 1995 | 29.475 | 1994 | 29.182 | 1993 | 28.89 | 1992 | 28.601 | 1991 | 28.312 | 1990 | 28.026 | 1989 | 27.741 | 1988 | 27.459 | 1987 | 27.178 | 1986 | 26.898 | 1985 | 26.621 | 1984 | 26.346 | 1983 | 26.072 | 1982 | 25.414 | 1981 | 24.503 | 1980 | 23.617 | 1979 | 22.75 | 1978 | 21.907 | 1977 | 21.087 | 1976 | 20.291 | 1975 | 19.515 | 1974 | 18.763 | 1973 | 18.033 | 1972 | 17.327 | 1971 | 16.641 | 1970 | 15.977 | 1969 | 15.336 | 1968 | 14.716 | 1967 | 14.116 | 1966 | 13.537 | 1965 | 12.978 | 1964 | 12.439 | 1963 | 11.919 | 1962 | 11.418 | 1961 | 10.936 | 1960 | 10.472 |
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