| Year | Value | | 2021 | 150.327435 | | 2020 | 73.431132 | | 2019 | 94.840477 | | 2018 | 64.710714 | | 2017 | 45.776862 | | 2016 | 126.052370637 | | 2015 | 121.567074708 | | 2014 | 134.10594055287 | | 2013 | 147.71151110211 | | 2012 | 79.895972431612 | | 2011 | 66.822175525801 | | 2010 | 71.894371680428 | | 2008 | 38.458 | | 2007 | 35.197 | | 2006 | 35.883 | | 2005 | 37.226 | | 2004 | 34.461 | | 2003 | 20.384 | | 2002 | 22.207 | | 2001 | 25.235 | | 2000 | 21.985 | | 1999 | 15 | | 1998 | 11.8999996185 | | 1997 | 32 | | 1996 | 18.2999992371 | | 1995 | 8.8999996185 | | 1994 | 7 | | 1993 | 5.4000000954 | | 1992 | 5 | | 1991 | 3.5999999046 | | 1990 | 2.7999999523 | | 1989 | 14.3999996185 | | 1988 | 14.1000003815 | | 1987 | 14.8000001907 | | 1986 | 9.3000001907 | | 1985 | 4.3000001907 | | 1984 | 3.9000000954 | | 1983 | 1.7999999523 | | 1982 | 14.3999996185 | | 1981 | 15.1000003815 | | 1980 | 2.7000000477 | | 1979 | 5.0999999046 | | 1978 | 3.5999999046 | | 1977 | 3.9000000954 | | 1976 | 4.6999998093 | | 1975 | 5.4000000954 | | 1974 | 3.5 | | 1973 | 2.9000000954 | | 1972 | 4.5 | | 1971 | 4.8000001907 | | 1970 | 4.1999998093 |
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