| Year | Value | | 2022 | 0.014120055797691 | | 2021 | 0.50610619443467 | | 2020 | 0.25223830341157 | | 2019 | 0.35991771445412 | | 2018 | 0.26560914050956 | | 2017 | 0.024920344029722 | | 2016 | 0.12822797838905 | | 2015 | 0.32203854927534 | | 2014 | 0.33339866665889 | | 2013 | 0.57726586473528 | | 2012 | 0.14072121935205 | | 2011 | 0.026363197129713 | | 2010 | 1.028023325725 | | 2009 | 0.0088769740229281 | | 2008 | 0.40218687665122 | | 2007 | 0.38648584669868 | | 2006 | 0.28317918122372 | | 2005 | 0.042162219762719 | | 2004 | 0.25687054484443 | | 2003 | 0.27519554474986 | | 2002 | 0.45857426832132 | | 2001 | 0.26654835861399 | | 2000 | 0.17809443709947 | | 1998 | 0.17841217935014 | | 1997 | 0.17873105740959 | | 1996 | 0.17905107737883 | | 1995 | 0.53908486348764 | | 1994 | 0.54200674693391 | | 1993 | 0.18099552452394 | | 1992 | 0.36101122240998 | | 1991 | 0.18001805041478 | | 1990 | 0.54102927282477 | | 1989 | 0.90827145743192 | | 1988 | 1.2856008101534 | | 1987 | 1.1152531950475 | | 1986 | 0.5623257554362 | | 1985 | 0.94429408002821 | | 1984 | 1.1450506787996 | | 1983 | 1.1583141089631 | | 1982 | 0.97561749453647 | | 1981 | 1.5810606026642 | | 1980 | 1.2024192966802 | | 1979 | 0.80972102326193 | | 1978 | 0.40568006956143 | | 1977 | 0.60545089087063 | | 1976 | 0.20140993717012 | | 1975 | 0.20181641562372 | | 1974 | 1.0152371464018 | | 1973 | 1.43887374521 | | 1972 | 2.3037668067017 | | 1971 | 1.70944333593 | | 1970 | 3.2861664484001 | | 1969 | 3.3978353641849 | | 1968 | 3.5173614178267 | | 1967 | 3.3983852815599 | | 1966 | 3.2625227316077 | | 1965 | 4.1672696400568 | | 1964 | 3.2435275753154 | | 1963 | 3.9220713153281 | | 1962 | 3.7850224131098 | | 1961 | 3.6257748022624 |
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