Year | Value | 2022 | 21.451 | 2021 | 21.008 | 2020 | 20.576 | 2019 | 20.153 | 2018 | 19.74 | 2017 | 19.336 | 2016 | 18.942 | 2015 | 18.557 | 2014 | 18.182 | 2013 | 17.815 | 2012 | 17.458 | 2011 | 17.108 | 2010 | 16.768 | 2009 | 16.434 | 2008 | 16.105 | 2007 | 15.781 | 2006 | 15.462 | 2005 | 15.149 | 2004 | 14.841 | 2003 | 14.538 | 2002 | 14.24 | 2001 | 13.947 | 2000 | 13.397 | 1999 | 12.857 | 1998 | 12.336 | 1997 | 11.834 | 1996 | 11.35 | 1995 | 10.883 | 1994 | 10.433 | 1993 | 9.999 | 1992 | 9.582 | 1991 | 9.18 | 1990 | 8.854 | 1989 | 8.541 | 1988 | 8.238 | 1987 | 7.944 | 1986 | 7.66 | 1985 | 7.386 | 1984 | 7.121 | 1983 | 6.864 | 1982 | 6.616 | 1981 | 6.376 | 1980 | 6.091 | 1979 | 5.816 | 1978 | 5.553 | 1977 | 5.302 | 1976 | 5.061 | 1975 | 4.83 | 1974 | 4.61 | 1973 | 4.399 | 1972 | 4.198 | 1971 | 4.005 | 1970 | 3.956 | 1969 | 3.911 | 1968 | 3.867 | 1967 | 3.823 | 1966 | 3.78 | 1965 | 3.737 | 1964 | 3.695 | 1963 | 3.653 | 1962 | 3.612 | 1961 | 3.571 | 1960 | 3.48 |
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