| Year | Value | | 2021 | 13.560057648 | | 2020 | 0.617193348 | | 2019 | 0.758181 | | 2018 | 0.711155 | | 2017 | 1.236961352 | | 2016 | 1.37789973 | | 2015 | 2.5494327762979 | | 2014 | 2.9066668132364 | | 2013 | 3.672312 | | 2012 | 2.1282547665725 | | 2011 | 5.7230194304506 | | 2010 | 7.5285400592246 | | 2009 | 0.365 | | 2008 | 0.464 | | 2007 | 0.288 | | 2006 | 0.324 | | 2005 | 0.3 | | 2004 | 0.283 | | 2003 | 0.283 | | 2002 | 0.248 | | 2001 | 0.256 | | 2000 | 0.328 | | 1999 | 0.3000000119 | | 1998 | 0.3000000119 | | 1997 | 0.3000000119 | | 1996 | 0.3000000119 | | 1995 | 0.400000006 | | 1994 | 0.3000000119 | | 1993 | 0.3000000119 | | 1992 | 3.7999999523 | | 1991 | 9.3999996185 | | 1990 | 10.3000001907 | | 1989 | 4.6999998093 | | 1988 | 3.7999999523 | | 1987 | 8.6999998093 | | 1986 | 10.8000001907 | | 1985 | 5.4000000954 | | 1984 | 5.4000000954 | | 1983 | 4.8000001907 | | 1982 | 5.4000000954 | | 1981 | 13.1000003815 | | 1980 | 11 | | 1979 | 8.3999996185 | | 1978 | 8.1000003815 | | 1977 | 6.8000001907 | | 1976 | 6.3000001907 | | 1975 | 4.5999999046 | | 1974 | 3.4000000954 | | 1973 | 3.5999999046 | | 1972 | 4.0999999046 | | 1971 | 3.0999999046 | | 1970 | 1.1000000238 |
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