| Year | Value | | 2020 | 2.781249 | | 2019 | 0.288954 | | 2017 | 0.418783315 | | 2016 | 0.358277746 | | 2015 | 0.46165020845874 | | 2014 | 0.31788 | | 2013 | 0.36126 | | 2012 | 0.7676275685 | | 2011 | 0.225400162 | | 1996 | 0.1000000015 | | 1995 | 0.1000000015 | | 1994 | 0.1000000015 | | 1993 | 0.1000000015 | | 1992 | 0.1000000015 | | 1991 | 0.1000000015 | | 1990 | 0.1000000015 | | 1989 | 0.1000000015 | | 1988 | 0.1000000015 | | 1987 | 0.1000000015 | | 1986 | 0.1000000015 | | 1985 | 0.1000000015 | | 1984 | 0.1000000015 | | 1983 | 0.1000000015 | | 1982 | 0.1000000015 | | 1981 | 0.1000000015 | | 1980 | 0.1000000015 | | 1979 | 0.1000000015 |
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