| Year | Value | | 2021 | 109.74070711301 | | 2020 | 114.41256679301 | | 1978 | 89.158244128785 | | 1977 | 90.744920354923 | | 1976 | 88.000002313043 | | 1975 | 91.830991278979 | | 1974 | 92.061858962483 | | 1973 | 94.487182857824 | | 1972 | 96.796665438273 | | 1971 | 99.757272046423 | | 1970 | 96.696319301908 | | 1969 | 98.422710605141 | | 1968 | 99.83818819163 | | 1967 | 102.25763029776 | | 1966 | 101.58730400605 | | 1965 | 98.8962500787 | | 1964 | 95.277767484568 | | 1963 | 93.491117261301 | | 1962 | 85.365849890938 | | 1961 | 87.044526068285 | | 1960 | 86.776852059286 |
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