| Year | Value | | 2021 | 0.000590054 | | 2020 | 8.624E-5 | | 2019 | 0.0024640038369081 | | 2018 | 0.0108797367 | | 2017 | 0.0108797367 | | 2016 | 0.007249968 | | 2015 | 0.005467548 | | 2014 | 0.005484 | | 2013 | 0.005484 | | 2012 | 0.31700301922356 | | 2011 | 0.509 | | 2010 | 0.554163455 | | 2009 | 1.384 | | 2008 | 1.589 | | 2007 | 1.438 | | 2006 | 1.601 | | 2005 | 1.364 | | 2004 | 1.289 | | 2003 | 1.176 | | 2002 | 1.246 | | 2001 | 0.798 | | 2000 | 0.8 | | 1999 | 0.8000000119 | | 1998 | 3.5 | | 1997 | 3.9000000954 | | 1996 | 3.5 | | 1995 | 3.5 | | 1994 | 3.2999999523 | | 1993 | 2.9000000954 | | 1992 | 1.6000000238 | | 1991 | 1.3999999762 | | 1990 | 0.8999999762 | | 1989 | 0.8999999762 | | 1988 | 0.6999999881 | | 1987 | 0.6000000238 | | 1986 | 0.6000000238 | | 1985 | 0.8000000119 | | 1984 | 1 | | 1983 | 0.6999999881 | | 1982 | 1.2000000477 | | 1981 | 1 | | 1980 | 0.8000000119 | | 1979 | 4.6999998093 | | 1978 | 6.8000001907 | | 1977 | 6.5999999046 | | 1976 | 4.5 | | 1975 | 3.4000000954 | | 1974 | 1 | | 1973 | 0.8000000119 | | 1972 | 0.6000000238 | | 1971 | 0.5 | | 1970 | 0.400000006 |
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