Year | Value | 2021 | 1.646 | 2018 | 1.36 | 2016 | 1.296 | 2012 | 1.132 | 2009 | 0.94 | 2007 | 1.649 | 1999 | 1.135 | 1997 | 0.932 | 1995 | 0.98 | 1992 | 1.03 | 1990 | 1.064 | 1989 | 1.035 | 1988 | 0.965 | 1987 | 0.983 | 1986 | 0.984 | 1985 | 0.929 | 1984 | 0.908 | 1983 | 0.902 | 1982 | 0.846 | 1981 | 0.76 | 1980 | 0.716 | 1979 | 0.692 | 1975 | 0.526 | 1970 | 0.521 | 1965 | 0.605 | 1960 | 0.51 |
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